This commit reverts the saas-12.2 editor by putting back the editor
of Odoo 12.

The saas-12.2 editor was an intermediate work between the previous
editor of Odoo 12 and the new one slated for Odoo 13. It was unstable
but it was supposed to be replaced by the new editor of version 13.

However, since the new editor has been postponed to Odoo 14, the
saas-12.2 one would have been staying in Odoo 13, which would have
been a nightmare to maintain. To avoid this outcome, we chose to
put back the 12.0 editor in its place.

This has the particular advantage that Odoo 13 will share the same
bugfixes as Odoo 12 and 11 as they all run under the same core
editor, while the saas-12.2 one would have been an entirely
different beast to maintain.

This is a partial revert of f2969923.

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>

Do not remove block in _removeNextEmptyUnbreakable.

Before this commit, when you tried to remove insert a character in
a td, with an empty td after the first one. The function
_removeNextEmptyUnbreakable removed the empty td. It was for
example breaking snippet in the website and mass_mailing.

closes odoo/odoo#32096

Signed-off-by: Adrien Dieudonné (adr) <adr@odoo.com>

For the ours need, we can not let the contentEditable behavior. Indeed,
this one does not have the same behavior according to the browser. The
DOM node could be erase, merge, cut, in them according to the keyboard
interactions. The problem is that if we have to manage these behaviors,
we have to manage everything. It was already the case in the previous
version, however before we created an editor by zone and by a hack we
mix the history.
In the case of the virtual keyboard of some OS / Phone, the events are
different and the autocompletion does not update (bug that prevents
modification interactions with javascript). In order to solve these
problems, we use another event for the insertion of the characters.
However, we must also force the update of the corrector by forcing a blur
and a focus.
The current version is a temporary version. We are currently working on a
version that uses a virtual dom and does not need to do excessive prevent
default.

closes odoo/odoo#35119

Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>

closes odoo/odoo#35059

Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>