Port HdyTabView/HdyTabBar
This took a while.
There are some issues with long press and DND visuals, but those are GTK and mutter issues:
- mutter#1523 (closed)
- gtk#2341 (closed)
- Drag icon doesn't resize, still need to report
Those shouldn't be blockers for libadwaita though.
Edited by Alice Mikhaylenko