Refactoring of the control panel with the Owl framework.

The MVC structure of the control panel has been changed to a 'component <-> model'
relationship. As such:
- Removed the old control panel: view/model/controller/renderer
- Created a new Owl Component (ControlPanel)
- Created a new class: the Model (an Owl Store did not fit here) and a newly
  designed ControlPanelModel extending it

Refactored all inner subcomponents, including:
- Pager
- ActionMenus (peviously SideBar)
- Filter menu
    > Custom filter item
- Group by menu
    > Custom group by item
    > Removal of groupby_menu_mixin (and refactored graph controller in sibling commit)
- Time range menu
- Favorite menu
    > Custom favorite item
    > Moved the favorite menu registry to the favorite_menu file
- Search bar
    > Removed and splitted auto-completion dropdown logic between the new SearchBar
      Component (descriptions) and to the new ControlPanelModel (domains).

The templates (all in web/base.xml) have been adapted to the new standards. Most
of the DOM structure remains unchanged with some occasional improvements (replace
hiding with not rendering, removed pointless wrapper divs, etc.).

Part of task 2196029

Co-authored-by: Mathieu Duckerts-Antoine <dam@odoo.com>

Be in Right to left

Open a m2o search more, to get onto the list modal
toggle the filters menu

Before this commit, the filters dropdown was almost invisble
and too much on the right anyway

This was because the RTL was not taken into account

After this commit, we anchor the dropdown on the right
(both as in good and as in side) side of its trigger button

Also, when modifying the dropdown, by developping the Custom Filter
we force the repositioning of the dropdown, to take those new elements
into account

It is expected though that after this commit, in RTL, the
dropdown in a modal that has a scrollbar (which is on the left)
will be slightly pushed to the right. It is usable and visible though
Some kind of plumbing using $el.data('offset', fn) from popper.js
is possible, but has been deemed not robust enough

Docs
https://getbootstrap.com/docs/4.0/components/dropdowns/#methods

OPW 2088934

X-original-commit: 105b4affd65ea23e1aa65b53f4595c174c9984ef

This branch introduces a large-scale reorganization of the
component tree generated by the web client.  The short version is
that now, the control panel is a child of the view controller and
no longer a sibling. Graphically (and simplified), we go from
this:

                  webClient
                 /    |    \
               ...   ...  actionManager
                           /         \
                   controlPanel   viewController
                                    /       \

to this:

           	  webClient
                 /    |    \
               ...   ...  actionManager
                               |
                          viewController
                            /   |   \
          ControlPanelController
              /           \
         CPRenderer     CPModel

The motivation is that this work moves the code where it should be.
Before this commit, it was kind of weird to have code in the
controllers to render buttons outside of their root node (in
renderButtons).  Also, the action manager had to take care of
coordinating search view states between view transitions.

So, this work simplifies the code.  It also makes it easier to
extend. We see day after day that Odoo needs to take care of more
complex UI needs, and in many cases, these needs were quite
difficult to implement (we prefer spaghettis in our plates, not in
our code).  The changes in this branch should open the way to
implement these features.

For example,
- it will now be easy to add the possibility of views (for example,
  the search view or a new ControlPanel view) to add custom buttons
  (of type action or object) in the control panel.
- Another need will be to serialize/ restore the state of the
  search view across action boundaries (needed by the dashboard).
- Another example is the possibility for views to customize easily
  the presence/absence of sub menus (filters/groupbys/favorites/
  time range/...)
- Another need is an easier way for views/client action to customize
  their control panel.

This commit also contains a large rewrite of the search view (so it
is more inline with our architecture and easier to maintain).

Part of task 1893568

Co-authored-by: Aaron Bohy <aab@odoo.com>
Co-authored-by: Mathieu Duckerts-Antoine <dam@odoo.com>
Co-authored-by: Martin Geubelle <mge@odoo.com>

Have a many2one, click on search more

Open the filter menu of the search view

Add custom filter

Click to select a field

Before this commit, the whole dropdown closed

After this commit, it doesn't

OPW 1911337

closes odoo/odoo#28969

A lot of new features have been implemented in search view
but autocompletion was forgotten. This commit fixes many
small problems that were introduced:

	- synchronization of facets created through
		autocompletion with filters and groupby menus
	- filters created through autocompletion can be saved

- The dropdown structure was simplified, allowing to get rid of the
  3-levels structure induced by <ul/> elements and dropdowns can now
  contain anything. The class 'dropdown-item' is now mandatory for
  each dropdown clickable element. The class 'dropdown-item-text' can
  be used to add same padding and style but without making the element
  have a clickable look.

- Dividers now use the class 'dropdown-divider'

- The way dropdowns are opened and hidden also changed (before the
  'open' class was added on the `.dropdown-menu` parent, now the
  'show' class is added on both the `.dropdown-menu` parent and the
  `.dropdown-menu` itself).

- JS-wise, no click event handlers can be put on `.dropdown-toggle`
  elements anymore (instead, use handlers for dropdown events).

- Carets are automatically put on `.dropdown-toggle` elements, so this
  commit replaces the `.caret` elements with this. This feature was
  possible to disable but would prevent us from adding a caret with
  scss. Also, this simplifies the DOM. The 'o-no-caret' class was also
  introduced to allow using the 'dropdown-toggle' class on non-caret
  elements.

- Also adapt the scss to use $caret-width instead of $caret-width-base

BS4 "btn-default" class was replaced with "btn-secondary", which makes
more sense.

Odoo made the bad choice of using the 'btn-sm' class for every button
instead of configuring the padding for default 'btn' to be smaller.
In BS4, the style of btn-sm is actually more complex, lowering the
font-size too. Also, btn-xs was removed so we would not have the
possibility to display smaller button than our default ones.

This commit removes btn-sm wherever it was used. Unfortunately, this
might remove it at some places where it made sense but this can be
restored in a second time.

Resulting in sphinx warnings or ill-formatted doc all the way to the
doc not building at all.

In the filters menus, the order of groups of filters comming
from the search view arch was not always preserved in the filters menu.
This commit fixes that situation.

forward-port of @4094f755