Django-ckeditor-link

- skip 0.5.2 due to github action / pypi troubles
- no functional changes
- REMOVE print statement
- introduce pre-commit / ruff / black and other goodies
- remove python 3.7 from test matrix

- introduce CKEDITOR_LINK_MODEL_USE_FILER_ADDONS, to enable usage of
django-filer-addons.filer_gui.fields.FilerFileField in ckeditor_link.link_model
(instead of the default filer field).

- add compatibility and tests for django 4.2

- ?

- fix broken get_link_text for foreign key links

- fix broken package