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 '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.

Add missing migration

See merge request !565

Resolve "Update to Django 3.2"

Closes #421

See merge request !564

Update lockfile

See merge request !561

Resolve "[Docker] Review handling of volumes"

Closes #403

See merge request !543

This allows making the STATIC_ROOT read-only

Requires django-sass-processor 1.0

Resolve "[DOM] Found 2 elements with non-unique id #language-select"

Closes #418

See merge request !558

Resolve "404 pages broken due to django-menu-generator-ng"

Closes #411

See merge request !557

[Docker] Do not generate a secret key on startup

See merge request !556

This would require www-data to be able to write the secret key now.
That would not be an issue in general, but requires awkward changes
with no real use. Users are supposed to configure a secret key
themselves.

Update dependency calendarweek to ^0.5.0

See merge request !555

Merge branch '413-docker-allow-using-core-image-as-base-image-for-app-distribution-images' into 'master'

Resolve "[Docker] Allow using core image as base image for app/distribution images"

Closes #413

See merge request !550

Resolve "style.scss uses deprecated SCSS"

Closes #410

See merge request !551

Resolve "Can't connect to Redis with default configuration"

Closes #414

See merge request !553

Update dependency celery-progress to ^0.1.0

See merge request !546