Merge branch 'new-model-based-on-calendar' into 225-introduce-substitution-to-do-list-generated-from-teachers-absences

Fix tests with Core 4.0.0.dev2

See merge request !332

Resolve "Adapt to Core 4.0"

Closes #210

See merge request !307

Update tox.ini

See merge request !316

Update .dev-js/package.json

See merge request !325

Update pyproject.toml

See merge request !323

Update .gitignore

See merge request !324

Merge branch '211-implement-vue-substitution-frontend' into 225-introduce-substitution-to-do-list-generated-from-teachers-absences

Update pyproject.toml

See merge request !322

Update package.json

See merge request !317

Update pyproject.toml

See merge request !313

Release 3.0.2

See merge request !312