WIP: Ability to add pinned shortcuts to maps on home screen

Marked WIP as it's in need of an icon for the launcher shortcut. I thought it might look best with a plain background and the map icon, ala the pinned shortcuts here, but I wasn't sure the best way to achieve that, especially as the majority of the rest of the icons used in the project are vector based. Any ideas?

The functionality should work on Android 7.1+ but I've only tested it on v9 so far. v8 and v9 should both work, but support for v7.1 is via a compatibility layer that I haven't verified.