[WIP] Location sharing

[sw1ftc0d3r]

Absorbing #51.

Things to be addressed:

• red pin is not correctly positioned when zooming in or out or rotating the map set the anchor point
• common classes and derivates for fragments
• map/satellite menu items should be radio items
• message type in details should be "Location message"
• message snippet in conversations view shows the Google Maps URL (should show "Location")
• fix up some XMPP related classes (e.g. move UserLocation to client-common-java)
• test orientation change/pause-resume cycle (especially map/satellite checked state consistency)
• rename maps settings section to location
• maps URL generation currently hard-coded into PositionManager
• check fallback behaviour to OSM when Google is not present on the device (try emulator)
• Can't find method 'requestRouteToHost(int,int)' in class android.net.ConnectivityManager targeting SDK version 26 osmdroid/osmdroid#633 (safe since getRouteToPathExists is never used)
• is OSM satellite available? If not, do not display choice in menu

Optional:

• sharing a location message should give the opportunity to actually share the text data instead of the location (subject to opinions actually) converted to "go to maps" button for now; sharing message disabled
• common classes and derivates for send fragments (moved in Location sharing (part 2) #1056)
• use different pin icons for OSM and Google Maps (moved in Location sharing (part 2) #1056)
• map/satellite state consistency after orientation change (moved in Location sharing (part 2) #1056)