misc: implement frameless window

Several major changes to the layout have been made.
- The chat search bar is moved into the message search layout.
- The Searchbar component is stripped of unused features.
- Some remaining logic that was used to switch main loader components is removed.
- ViewCoordinator.getView gets a "force create" parameter and we no longer preload low-cost views.

NOTE: the option to use a frameless window is available within general settings

Gitlab: #1524 (Frameless Window)
Change-Id: Iec6bdf162cb0335d3ae3d9bd09dd9783991a4a57