Drop the Bridge theme and completely migrate to material. This is for
two reasons:
- To make Material You less painful
- Improve coloring [Dark mode, other colors, etc].
Most of the previous UI elements were kept [no rounded corners], but
did come at the cost of removing the hint tagline from the search bar
since there was simply no good way to integrate it. There are also
some other miscellanious issues [Weird selection menus, dividers are
not migrated still], but those will be fixed in future commits.
