Correction of the position of the buttons when editing bg-image
position with a parallax effect other than "fixed".

task-46147

closes odoo/odoo#48419

X-original-commit: 0919b11c9a78a97345b42bf0fe0f1f9939c2b214
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

* website, mass_mailing, website_event, website_form,
  website_mass_mailing, website_sale

Now the user can save snippets to use them on other pages.

task-2120409

closes odoo/odoo#40408

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>
Co-authored-by: qsm-odoo <qsm@odoo.com>

Previously, background size and position for snippets was configured in
a modal, the user could choose a "focus point", which is rather
unintuitive. They could also choose to use the "contain" background
mode, with or without repeat, or a third option, where they could
customize everything, from the background size in both directions to
whether to repeat the background in only one or in both directions.

This commit streamlines the background-sizing options, only the "cover"
and "repeat pattern" options have been kept, as they cover almost every
use case. Their configuration has been moved into the options menu for
consistency with the rest of the editor, and the background's position
is now chosen by clicking on the corresponding menu option, and dragging
the background to the desired place.

Part of https://github.com/odoo/odoo/pull/38959
maintask-2066614
task-2088304

The wysiwyg abstraction layer was introduced in saas-12.2 by
commit f2969923. Its goal was to provide an external interface
for other modules that wanted to use the editor feature such
that the editor core itself could be changed without requiring
extensive changes in the other modules.

This commit is adapting the wysiwyg interface to instantiate
the 12.0 editor below it rather than the saas-12.2 one, thus
reverting the "new editor" part of f2969923 itself.

Part of PR 35677.

Co-authored-by: Nicolas Bayet <nby@odoo.com>
Co-authored-by: Antoine Guenet <age@odoo.com>
Co-authored-by: Christophe Matthieu <chm@odoo.com>
Co-authored-by: David Monjoie <dmo@odoo.com>

* web_editor

BS conflicts with our UI again: btn sizes and form controls are
more difficult to force with BS4, this commit adapts the controls to
use less problematic sizes, and adds/adapts some more forcing rules.

Part of https://github.com/odoo/odoo/pull/31117
task-1941156

* Simplify the code
* Make the feature mork without unsplash
* Handle corner cases

task-1896705

* web_unsplash, website_sale

- Visual improvements and cleaning in each tab: video, documents,
  pictogram, images.

- Only one search input for both the local library and unsplash.

- Replace the idea of multiple pages by adding a 'Load More' button.

task-1896705