Resolve "Do not allow to add personal notes for cancelled lessons"

Closes #82

See merge request !61

Resolve "Show lesson topic and group in week overview"

Closes #62

See merge request !75

Groups are only shown if the current page doesn't show a group

Resolve "[Full register] Only show personal notes of group members"

Closes #89

See merge request !70

Resolve "Add option to configure extra marks for personal notes"

Closes #85

See merge request !68

Resolve "[Lesson view] Organise information in tabs"

Closes #87

See merge request !69

Merge branch '88-ensure-that-full_register-only-counts-personal-notes-in-the-selected-school-term' into 'master'

Resolve "[Full register] Filter personal notes by school term"

Closes #88

See merge request !71

Currently translated at 99.2% (124 of 125 strings)

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

Currently translated at 10.0% (8 of 80 strings)

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

Currently translated at 10.0% (8 of 80 strings)

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

Currently translated at 73.7% (59 of 80 strings)

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

Currently translated at 100.0% (80 of 80 strings)

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

Currently translated at 100.0% (80 of 80 strings)

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

Archive groups of a person for every personal note to check against it
to decide what data should be displayed in full register print out

Resolve "Add support for group notes"

Closes #68

See merge request !65

Tabs: lesson documentation, personal notes and change history