Resolve "Adjust to RegistryObject classvar name change"

Closes #76

See merge request !217

Fix import of supervisions for non-existing breaks

See merge request !214

Delete .eslintrc.js

See merge request !211

Update .dev-js/package.json

See merge request !210

Update .dev-js/.eslintrc.js

See merge request !209

Update .gitignore

See merge request !208

Fix import of supervision substitutions

See merge request !212

Resolve "Adapt to moving of ValidityRange"

Closes #75

See merge request !203

Update pyproject.toml

See merge request !196

Fix import of supervision substitutions

See merge request !202

Update .dev-js/package.json

See merge request !197

Fix absence creation

See merge request !195

Resolve "Show imported extra lessons and events in substitutions table"

Closes #73

See merge request !194

Fix substitutions import

See merge request !193

Handle existing amends on LessonEvents

See merge request !192

Resolve "Cancel all lessons on group absences"

Closes #72

See merge request !191

Resolve "Events are deleted without reason"

Closes #69

See merge request !190

Migrate to Cursus/Lesrooster

See merge request !166