Prepare release 2.0

See merge request AlekSIS/official/AlekSIS-App-Untis!93

(cherry picked from commit 0057a5cc)

(cherry picked from commit 1f9c3447)

(cherry picked from commit c7b8e92b)

(cherry picked from commit 29a7f98d)

(cherry picked from commit 2c696274)

(cherry picked from commit 923d2157)

Prepare release 2.0rc3

See merge request AlekSIS/official/AlekSIS-App-Untis!88

(cherry picked from commit 7645d34d)

(cherry picked from commit e4060943)

Prepare release 2.0rc2

See merge request AlekSIS/official/AlekSIS-App-Untis!82

(cherry picked from commit bfcc6f33)

Prepare release 2.0rc1

See merge request AlekSIS/official/AlekSIS-App-Untis!77

(cherry picked from commit 68b2c778)

(cherry picked from commit 53e2eabd)

Update pyproject.toml, poetry.lock and tox.ini for 2.0b0

See merge request AlekSIS/official/AlekSIS-App-Untis!74

Update translation files

See merge request AlekSIS/official/AlekSIS-App-Untis!72

Update changelog for 2.0b0

See merge request AlekSIS/official/AlekSIS-App-Untis!71

Remove XML importer for now

See merge request AlekSIS/official/AlekSIS-App-Untis!70

This can be reverted completely when working on #7 outside of the release cycle.

Resolve "Rename rules to allow differentiation from permissions"

Closes #24

See merge request AlekSIS/official/AlekSIS-App-Untis!69

Update poetry.lock

See merge request AlekSIS/official/AlekSIS-App-Untis!68

Resolve "Extra lessons are imported without linked school terms"

Closes #23

See merge request AlekSIS/official/AlekSIS-App-Untis!67