Merge felix's changes from '256-add-simple-course-book-list'

...alsijil/frontend/components/coursebook/coursebook.graphql

...mponents/coursebook/documentation/DocumentationStatus.vue

...components/coursebook/documentation/LessonInformation.vue

...il/migrations/0020_add_documentation_and_participation.py

...ations/0020_documentation_extramark_colour_bg_and_more.py

...is/apps/alsijil/migrations/0022_documentation_teachers.py

.../0023_extramark_colour_bg_extramark_colour_fg_and_more.py

aleksis/apps/alsijil/models.py

aleksis/apps/alsijil/schema/__init__.py

aleksis/apps/alsijil/schema/documentation.py

aleksis/apps/alsijil/util/predicates.py