Move to CKEditor 5

[sveetch]

Is your feature request related to a problem? Please describe.

The problem with CKEditor 4 currently used as the rich text editor solution in Bireli is that is no longer maintained. Well in fact there is a possible security maintenance release planned until 2026 but this is need to be bought from CKEditor and finally the free version is really no longer maintained.

Describe the solution you'd like

We need to move to CKEditor 5, that is still free (with another payable version with more features) and with a look and feel similar to CKEditor 4.

Hopefully djangocms-text implements both CKEditor 4 and 5 versions and the user experience should be the same for users than the version 4. Except it does not implement yet the CMS feature for " text-enabled plugin" (which allows to insert other plugins in text by the way of private HTML tags) but we are not enabling it for the version 4 as well (because of impossibility to disable some plugin we did not want in this plugin menu).

In fact the real problem with CKEditor 5 is that we still use django-ckeditor app for non CMS applications (like Lotus) which use CKEditor 4 and i've not really checked a migration to django-ckeditor-5 was possible yet. Also we need to provided similar experience between CMS and non CMS apps.

Describe alternatives you've considered

Keeping CKEditor 4 is not a proper solution because it has security flaws that are regularly raised from security audits. The security flaws are a little bit difficult to apply but they exist. So we can keep it longer.

TipTap is not a possible solution because it lacks a lot of features (text-enable plugin, editor plugin to view/edit HTML source, etc..).

[sveetch]

Issue with CKEditor and content creation/edition has been fixed, so we can enable CKEditor 5 in CMS then start to see for the non-cms apps migrations.

However Bireli v0.4.0 will be released without it, the lack of some ckeditor plugins and non-cms apps migrations is too much for this release awaited since a long time, we will probably see this in a next release.