Update changelog from 2.0

See merge request !94

(cherry picked from commit 69336497)

Resolve "Management commands are not run in the frontend"

Closes #29

See merge request !91

Update poetry.lock

See merge request !92

Provide demo data

See merge request !90

Update changelog from 2.0rc3

See merge request !89

(cherry picked from commit 9778e774)

Resolve "Assign rooms correctly"

Closes #27

See merge request !84

Resolve "Skip extra lessons without a subject"

Closes #28

See merge request !87

Update poetry.lock

See merge request !86

Update poetry.lock

See merge request !85

Update changelog from 2.0rc2

See merge request !83

(cherry picked from commit 7915b78d)

Merge branch '26-validity-ranges-are-linked-to-terms-only-by-untis-id-and-not-by-school-term' into 'master'

Resolve "Validity ranges are linked to terms only by Untis ID and not by school term"

Closes #26

See merge request !81

Wrap the complete import in an atomic revision

See merge request !80

Update poetry.lock

See merge request !79

Update changelog from 2.0rc1

See merge request !78

(cherry picked from commit 65dd9dd6)

Update translation files

See merge request !76

Use gettext_lazy for preference section verbose names

See merge request !75

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

See merge request !74