Merge branch '18-untis-globalpermissions-aleksis-core-w002-model-globalpermissions-in-app-config-aleksis-apps' into 'master'

Resolve "untis.GlobalPermissions: (aleksis.core.W002) Model GlobalPermissions in app config aleksis.apps.untis doesnot derive from aleksis.core.mixins.ExtensibleModel"

Closes #18

See merge request !53

Fix testsuite

See merge request !52

Update tox.ini. Advances AlekSIS-Core#338

See merge request !50

Update tox.ini. Advances AlekSIS-Core#338

See merge request !49

Merge branch '15-substitutions-and-maybe-other-data-entries-aren-t-deleted-if-they-are-out-of-validity' into 'master'

Resolve "Substitutions (and maybe other data entries) aren't deleted if they are out of validity"

Closes #15

See merge request AlekSIS/official/AlekSIS-App-Untis!48

Resolve "Filter by term while importing supervisions"

Closes #16

See merge request !47

Out of validity = Linked to a validity, but the validity range ends before the substitution's date

Close #15

Close #16

Currently translated at 100.0% (38 of 38 strings)

Translation: AlekSIS/AlekSIS-App-Untis
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-app-untis/de/

Resolve "Import supervisions being linked to a validity range"

Closes #12

See merge request !46

Resolve "Import absences correctly"

Closes #11

See merge request AlekSIS/official/AlekSIS-App-Untis!45

Set comment in revision to attribute the deletion to the importer

See merge request !44

Resolve "Set teachers list to [] if there are no old teacher and no new teacher"

Closes #10

See merge request !42

Make lint clean

See merge request !41

Enable prometheus exporter for MySQL database backend.

See merge request !40

Use setuptools entrypoint to register app

See merge request !39