Refactor: Use class-based views

Turn all views in all apps into class-based views: https://docs.djangoproject.com/en/3.0/topics/class-based-views/

• Identify different views and which views are similar enough to turn into a base view class, with overrides either through as_view or through inheritance or mixins
• If it makes sense across apps, create base view classes in AlekSIS core
• Move reusable code out of the views into util in each app, or even in AlekSIS core
• Turn all views in all apps into class-based views finally

added part::backend prio::2 labels

assigned to @sstoffels and unassigned @nik

changed the description

@sstoffels Please give an update about the issues you took responsibility for.

Invested 5 hours until now (2 for my initial test-installation, see merge-request concerning installation-hints) First, I moved the most obvious views: "persons" and "groups" to classbased, first had to learn, that the usual ListViews cannot be used with render_table (when queryset is customized). Therefore, this documentation is helpful: https://django-tables2.readthedocs.io/en/latest/pages/tutorial.html

Some testdata to import into my test-instance would be appreciated now.

unassigned @sstoffels

added part::backend prio::2 labels

changed milestone to %2.0a2

mentioned in issue #212 (closed)

removed milestone

removed milestone

changed the description

marked this issue as related to #122 (closed)

removed prio::2 label

added prio::1 label