Merge branch 'master' into 357-support-pdf-generation-via-electron-pdf-running-in-the-background-using-celery

[Docker] Base on debian:bullseye-slim

See merge request !574

* We get Python 3.9 from Debian
* We can use uWSGI from Debian
* We get postrgedql-client 13 (so pg_dump in dbbackup can dum pfrom PostgreSQL 13)

Resolve "[Backup/Storage] Improve configuration and enable S3"

Closes #424

See merge request !573

Remove path_and_rename

See merge request !562

Merge branch 'master' into 357-support-pdf-generation-via-electron-pdf-running-in-the-background-using-celery

Translations update from Weblate

See merge request !529

Silence stupid cachalot version check

See merge request !571

https://github.com/noripyt/django-cachalot/issues/175

Update dependency django-phonenumber-field to <5.2

See merge request !570

Merge branch 'master' into 357-support-pdf-generation-via-electron-pdf-running-in-the-background-using-celery

Merge branch '422-add-django-cleanup-to-delete-media-files-related-to-deleted-objects' into 'master'

Resolve "Add django-cleanup to delete media files related to deleted objects"

Closes #422

See merge request !568

Resolve "post_migrate expects too many arguments"

Closes #423

See merge request !569

Denote Teckids e.V. as licensor as defined by EUPL

See merge request !567

This is important to clarify the jurisdiction and court location in case of
license disputes.

Merge branch 'master' into 357-support-pdf-generation-via-electron-pdf-running-in-the-background-using-celery

Add missing migration

See merge request !565