New Owl component: Dialog. It does not rely on Bootstrap but behaves the same
and does not conflict with legacy dialogs.
To call this component, you need to define it in the XML parent template instead
of calling it in the JS file, and put a flag in the parent state to toggle the dialog.
Old dialog file has also been slightly updated to ensure compatibility between both
versions.

This commit also updates a list view test which did not wait for click events to
properly trigger and would cause the new dialog system to crash.

Now we can display dialogs with or without header / footer / backdrop
and we can force the DOM to be put elsewhere than the body.

Part of https://github.com/odoo/odoo/pull/29353
task-1903256

Currently, to remove link of x2m field from any record, sometimes there's no way.
For example, if we are on mobile and open any Quotation, it's linked quotation lines
are automatically converted in kanban, and there is no way to delete a line from
that quotation. However, in some of the manually designed kanban, there is special 'x'
for removing / unlinking x2m record, for example, Contacts of Partner.

This commit makes the behavior more consistent. During edition (mobile and desktop), if
a view dialog is opened on click of x2m field, it will have one 'Remove' button (based
on user rights) on right side of dialog footer, allowing users to delete / unlink the
record. Moreover, in mobile, the modal is opened fullscreen, with sticky header and
footer.

Related Task# : 31641
Closes PR #15857

Co-authored-by: Mohammed Shekha <msh@openerp.com>

* web, website

- JS Modals were not correctly built anymore, their .modal-body element
  was duplicated and many without-effect JS lines were introduced (as a
  side effect, the form view design was broken when inside modals)

- Tests were changed to make bugs go unnoticed. For example, the media
  dialog functionnality was entirely broken because the .modal-dialog
  element was not receiving the correct class anymore.

- The JS translation function is _t, not _

- Do not use the <title/> tag as a regular DOM element, it is meant to
  be unique, in the <head/> section

- CSS rules were added to the utils.scss file, which is meant to contain
  functions and mixins, otherwise, the rule is duplicated in every asset

- Some icons were still broken, as missed by https://github.com/odoo/odoo/commit/f90cf060a3cfeb37a67bec83264c0aaab8892b56

- Tests were changed to use [role="dialog"]/footer/header in their
  selectors without any reason, this commit restores some of that to
  avoid rebase conflicts with the BS4 work.

- ...

Note: other elements should still be discussed, like the direct use of
the 'o_form_label' class in views definition... but those do not cause
direct problems.

Today, Odoo is really tricky to use without seeing the screen, it must be improved to be usable.

This PR forbid to use labels without a "for" attribute, add some title, rule and aria attributes in HTML. With that, Odoo will be fully usable with a screen reader.


* [IMP] Labels must have a for attribute. Improve accessibility.
* [IMP] Better error message when trying to read a missing cached value
* [FIX] Add some aria-label and title attributes for screen readers.
* [FIX] Template name is not included in the error message in case of SyntaxError in QWeb
* [FIX] Improve the Tour failed at step error message to be more explicit.
* [IMP] Add aria-labels
* [FIX] Add missing aria-label on failing test
* [IMP] aria-hidden means hidden. Fix all bad aria-hidden and hide aria-hidden for all.
* [IMP] Color names on kanban views and many2many tags
* [IMP] Add some checks on views for accessibility.
* [IMP] Add `alt` attribute on `img` tags.
* [IMP] Add aria-label and title on non-described icons
* [IMP] Add button role to widgets with btn class
* [IMP] Translate aria and formatted attributes.
* [IMP] Remove wrong aria-labelledby
* [IMP] Add menu role on dropdowns
* [IMP] Buttons must be focusable
* [IMP] Add aria attributes on progress bars
* [IMP] Improve accessibility of basic widgets
* [IMP] Change main layout to more semantic tags
* [IMP] Add menuitem role when missing
* [IMP] Remove wrong role='presentation'
* [IMP] Improve accessibility of tab panels
* [IMP] Add aria-invalid on invalid fields
* [IMP] Add aria-sort on ordered columns
* [IMP] Add role on alerts
* [IMP] Use dialog role, header, main and footer tags for modals
* [IMP] Add labels on o_status
* [IMP] Improve accessibility of kanban view with feeds and articles
* [IMP] Add alerts in case of new messages
* [IMP] Add widget, navigation or img role to aria-labelled items

The goal of this commit is to allow fast entry of the same model using
the keyboard for navigating through the form once, by blocking the user
from advancing in the form if there is a required field or once they
went through the form once to get them to a primary action (button)

This commit includes the following changes
    1) Enable moving forward from field to field using the TAB key
    2) Entering the one to many and many to many using the TAB key
        a. When entering it, set the focus on the "add new line" link or
            button
		b. When adding a new line, set the focus on the field visible
            editable field of the new line
        c. Discard adding a new line with ESC key
        d. If the user leaves the first field empty and uses TAB, we
            will cancel the adding of a new line and move to the next
            field of the form
    3) When a field is required and not filled in, do not allow the user
        to move out of the field using the TAB key (the user is still
        allowed to use the mouse though), mark the field as invalid
        instead
    4) After going though the form once, using the TAB key on the last
        field will move the focus to the first primary button of the page
    5) When the focus is on a primary button (EDIT/SAVE), the user cannot
        move the focus forward using the TAB key. Hitting TAB again will
        display a tooltip telling to hit ENTER to activate the button.
        The mouse is still available to move the focus.
    6) When the user saves, the focus is placed on the first primary
        button of the form renderer (like VALIDATE for a new invoice)
    7) On dialogs, primary buttons should stop the users from moving out
        of them, and showing a popup if the user tries
    8) When closing a dialog, the focus will be moved back to the widget
        that opened it.

This commit does not include the following features
    1) Navigation with the keyboard on a selection one to man
    2) Navigate between tabs in a form using the keyboard
    3) Cancelling the adding of a new line in a many to many using the
        ESC key do not set the focus correctly
    4) Enhancing the focusses fields (like blue underline)

Opening a modal in Odoo should be done thanks to the 'Dialog' class. In
the frontend, there can also be modals which are meant to be shown to
the unconnected frontend visitors and those should then get the style of
the website (bootstrap) and not the one of odoo. To manage this, the
website JS code was extending the Dialog class so that it adds the
'o_website_modal' class on modals which are opened thanks to the class.
The LESS code was then in charge of forcing the Odoo style on those.

This behavior is not the right one. "Visitors" modals should also be
able to be opened with the Dialog class. This commit is a first step
towards to the right behavior:
- The standard 'Dialog' adds the 'o_technical_modal' class on its root
  element by default and allows to not put it thanks to 'technical'
  options.
- 'o_website_modal' is then replaced by 'o_technical_modal'.

What should be done next is:
- Use the Dialog class when it is possible
- Move modal.less in the common assets and make it style only technical
  modals -> remove some forcing of the style on 'o_technical_modal' in
  the frontend

This behavior also allows future improvements, like building a
completely different structure for technical modals which would allow
better designing and the end of visitor/technical bootstrap conflicts
(and so LESS efficiency).

* web_editor, web_planner, website

The 'Dialog' class is used in both backend and frontend. Also, lots of
actions can be done without the use of any modal. It thus makes sense
to lazy load its related xml only when a first modal is opened.

This change also allows to get rid of the "base_common.xml" file as the
dialog template is the only remaining one in there and, in the future
website update, it will allow to not load any static XML file on website
page loadings.