Merge 'origin/266-add-statistics-page-for-absences'

aleksis/apps/alsijil/checks.py

...d/components/coursebook/absences/ManageStudentsDialog.vue

...omponents/coursebook/statistics/StatisticsForGroupTab.vue

...ponents/coursebook/statistics/StatisticsForPersonCard.vue

...ponents/coursebook/statistics/StatisticsForPersonPage.vue

...nts/coursebook/statistics/StatisticsPersonalNotesList.vue

...ponents/coursebook/statistics/StatisticsTardinessCard.vue

...ntend/components/coursebook/statistics/statistics.graphql

...d/components/injectables/group_actions/OpenCoursebook.vue

...end/components/injectables/group_actions/ShowAbsences.vue

aleksis/apps/alsijil/frontend/index.js

aleksis/apps/alsijil/frontend/messages/de.json

aleksis/apps/alsijil/frontend/messages/en.json

aleksis/apps/alsijil/model_extensions.py

aleksis/apps/alsijil/models.py

aleksis/apps/alsijil/preferences.py

aleksis/apps/alsijil/rules.py

aleksis/apps/alsijil/schema/__init__.py

aleksis/apps/alsijil/schema/documentation.py

aleksis/apps/alsijil/schema/participation_status.py