* adds needed migrations
* refactors forms.py (700+ lines) in main konova app
* splits into forms/ and forms/modals and single class/topic-files for better maintainability and overview
* fixes bug in main konova app migration which could occur if a certain compensation migration did not run before
* adds restorable delete functionality to Team model
* refactors minor code model parts by introducing DeletableObjectMixin
* only non-deleted Teams can be chosen for sharing
* deleted Teams can be restored using the proper function on the backend admin
* deleted Teams do not provide
* adds migration
* adds admin column on team index view
* refactors Team model, so multiple members can become admins
* adds team migration for switch from fkey->m2m structure
* renames 'Group' to 'Permission' on user index view to avoid confusion between 'Groups' and Teams
* adds new autocomplete route for team-admin selection based on already selected members of the TeamForm
