This was previously not keyboard navigable at all, making it
impossible to switch servers in this dialog solely with a keyboard. This
patch makes it possible to do some basic selection but not deletion yet,
but it's a good start.
(cherry picked from commit b11d46e34a)
Pull the generic aspects from Room search and join room pages into it's own component. This is done in anticipation of using the new generic search page for a user search functionality.
- `SearchPage` is now used for the generic version with the old one being renamed `RoomSearchPage`
- `JoinRoomPage` is renamed to `ExploreRoomsPage` inline with everywhere else in NeoChat
There is also some cleanup of the code for both search pages in here.
