Prefetch related data for lesson events

See merge request !351

Merge branch '245-group-types-that-are-managed-by-some-app-e-g-cursus-school-class-can-t-be-selected-as-timetable' into 'master'

Resolve "Group types that are managed by some app (e.g. cursus' "school class") can't be selected as timetable group type"

Closes #245

See merge request !350

Refactor timetable wrapper

See merge request !347

Resolve "Add for_participant manager"

Closes #243

See merge request !348

that returns all lessonEvent a person participates in.

Resolve "Return lesson events for partitipant"

Closes #244

See merge request !349

Resolve "Add preference for group type to show in timetable view"

Closes #216

See merge request !343

Translations update from Weblate

See merge request !336

Currently translated at 100.0% (30 of 30 strings)

Translation: AlekSIS/AlekSIS-App-Chronos-Frontend
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-app-chronos-frontend/de/

Currently translated at 20.0% (6 of 30 strings)

Translation: AlekSIS/AlekSIS-App-Chronos-Frontend
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-app-chronos-frontend/uk/

Currently translated at 20.0% (6 of 30 strings)

Translation: AlekSIS/AlekSIS-App-Chronos-Frontend
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-app-chronos-frontend/ru/

Currently translated at 63.3% (19 of 30 strings)

Translation: AlekSIS/AlekSIS-App-Chronos-Frontend
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-app-chronos-frontend/de/

Currently translated at 31.5% (6 of 19 strings)

Translation: AlekSIS/AlekSIS-App-Chronos-Frontend
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-app-chronos-frontend/uk/

Currently translated at 31.5% (6 of 19 strings)

Translation: AlekSIS/AlekSIS-App-Chronos-Frontend
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-app-chronos-frontend/ru/

Release 4.0.0.dev3

See merge request !341

Resolve "Remove legacy frontend"

See merge request !340

Resolve "Implement Vue substitution frontend"

Closes #211

See merge request !310

Fix some bugs with displaying lesson events

See merge request !339