Rewrite Map fragment location code to follow user and enable tracking

Summary:

• Add GPL notice to files

• Fix map location enabled

• Show alert when no location is granted

• Receive first location correctly

• Enable the position initally in the MapFragment only when the distance from the center of Turin is < 90 km

• Enable the position initially in the LineDetailsFragment only when the distance from the center of the view is < 20 km

• Create new FusedLocationProvider so that it works in Xiaomi phones, too

• Create permission singleton to cache the number of times we've asked for the location

Fix T1378

Test Plan:

1. Open the map screen, check that the position is visible and it is updated
2. Open the line screen:
   • Check that disabling and enabling the position works
3. Check that when the map screens are closed, the app stops using the location
4. Check that from far away the position is queried once (or no times) and immediately disabled
5. Check that when setting the location permission on "Ask every time" the app actually asks for the location

Reviewers: Libre BusTO hackers, valerio.bozzolan

Reviewed By: Libre BusTO hackers, valerio.bozzolan

Subscribers: valerio.bozzolan

Project Tags: Libre BusTO

Maniphest Tasks: T1378

Differential Revision: https://gitpull.it/D237