Feincms3

~~~~~~~~~~~~~~~~

- Added ``RegionRenderer.copy()`` and ``RegionRenderer.unregister`` methods to
allow modifying existing renderers without having to reach into internal
attributes. Refactored the internals to make client code fail early and
loudly if it tries to use old ways.

~~~~~~~~~~~~~~~~

- Tweaked the tree changelist background stripes to also show some of the
hierarchy.
- Replaced the unicode icons with material icons, they work everywhere.
- Fixed the width of icons in plugin inlines.
- Added the ability to add plugins to the renderer which aren't fetched from
the database. This is especially useful when used with the JSON plugin from
`django-json-schema-editor
<https://github.com/matthiask/django-json-schema-editor>`__.

~~~~~~~~~~~~~~~~

- Renamed the internal root middleware response to
``UseRootMiddlewareResponse`` so that it can be used in advanced or exotic
scenarios to allow the root middleware to run even after views return a 404
response.
- Switched from ESLint to biome.
- Changed the move node interface to a cut-paste based interface which works
directly in the admin changelist.
- Changed the ``TreeAdmin`` ``list_display`` and ``list_display_links`` to be
more useful by default.

~~~~~~~~~~~~~~~~

- Added Python 3.12, Django 5.0.
- Updated the signature of bundled ``render_*`` functions in
``feincms3.plugins`` to also accept a (for now optional) context parameter.
Previously those functions were not directly usable with
``RegionRenderer.register``.
- Move form: Use a potentially restricted ``ModelAdmin.get_queryset`` method
instead of the default model manager to generate potential targets.
- Improved the test coverage a bit.

~~~~~~~~~~~~~~~~

- Extended ``|translations`` to with the option to pass an alternative value
for ``settings.LANGUAGES`` as a second argument.
- Stopped automatically sizing the CKEditor on startup; it was always wrong
when using custom CSS.
- Enabled the source button now that we're using the classic CKEditor again.
- Restructured the private methods for clash checking so that feincms3-sites
and feincms3-language-sites can also narrow the applications check to their
needs.

~~~~~~~~~~~~~~~~

- Added the ``AbstractPageQuerySet.applications`` which makes it easier to
prepare a list of applications in the format ``apps_urlconf`` expects.
- Updated the CKEditor 4 script to the last open source version.
- Changed back to the classic CKEditor 4. It is with a heavy heart that I have
to declare bankruptcy for the inline approach. Overriding the Django admin
CSS is too cumbersome and has too many edge cases. You can revert to the old
behavior by changing setting ``FEINCMS3_CKEDITOR_URL`` and
``FEINCMS3_CKEDITOR_CONFIG`` to the `appropriate values
<https://github.com/matthiask/feincms3/blob/c45a2ed30cc9a69f7634d15e49bdf84b7fe15be5/feincms3/inline_ckeditor.py>`__.
If you haven't customized the CKEditor you do not have to change anything.
Future versions of feincms3 may switch to a different editor altogether,
since CKEditor 5 is a complete rewrite with a different license and CKEditor
4 uses a paid LTS model (which I totally understand, no hard feelings at
all).
- Dropped support for Python 3.8.