Update translation files

See merge request !201

Resolve ""Lesson documentation" tab missing in 'My overview' for teachers"

Closes #166

See merge request !202

Resolve "Preference section is German"

Closes #167

See merge request !200

Update maintainers and Trove categorisation

See merge request AlekSIS/official/AlekSIS-App-Alsijil!198

Set version and core dependency to 2.0b0

See merge request !196

Resolve "Fields must be unique per site"

Closes #163

See merge request !197

Resolve "Update feature list"

Closes #164

See merge request !194

Resolve "Fix rules/permissions"

Closes #165

See merge request !195

Update changelog for 2.0b0

See merge request !192

Translations update from Weblate

See merge request !193

Currently translated at 100.0% (250 of 250 strings)

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

Resolve "Rename rules to allow differentiation from permissions"

Closes #161

See merge request !190

Resolve "Sync Copyright in README.md and apps.py"

Closes #162

See merge request !191

Resolve "Update copyright"

Closes #160

See merge request !189

Merge branch '115-person-overview-implement-multiple-selection-for-marking-absences-as-excused-or-for-deleting' into 'master'

Resolve "[Person overview] Implement multiple selection for marking absences as excused or for deleting"

Closes #121 und #115

See merge request !111

Merge branch '157-permission-checking-decorators-raise-internal-server-error-if-the-user-is-anonymous' into 'master'

Resolve "Permission checking decorators raise internal server error if the user is anonymous"

Closes #157

See merge request !188