* Not just apps, also documents and contacts can now be added
to the favorites. All types of content have their full context
menu action list available also in the favorites sidebar.
* Contact favorites use the contact photo as icon, with a circular
alpha mask and the presence status icon as overlay badge.
* Adding/removing favorites from context menus now works every-
where, e.g. also in KRunner-based search results.
* Far fewer actions now cause a full rebuild of the model tree
and instead only delta updates, as a side-effect of adding a
mechanism for this to e.g. handle status changes for contact
items.
* Various bugs around hiding/unhiding apps got fixed.
* Lots of code cleanup + less coupling all around.
If menu flattening is enabled and a group actually has subgroups
that get flattened in, separators are ignored and entriees are
collated alphabetically.
Leading or trailing separators are always ignored, and multiple
consecutive separators are collapsed into one.
BUG:347412