Content group template selection routes
Following routes have been added:
/templates
/templates/<templateId>
Add new menu item to main menu for reaching templates route temporary.
For this make ContentGroupTemplateSelectionComponent
standalone and use as dialog optional.
When adding tags or switching language, it is added to the route as query params. So when navigating to preview and back to selection, the query params are used to store the correct state. This also enables to share a filtered tag selection via url.
Also create AddTemplateButtonComponent
and RoomSelectionComponent
for adding templates from different components and selecting a room if content group template selection is used outside of a room.
Closes #1210 (closed)