Add support for specifying fixed RTK base position

AirspaceManager is now exposed by QGroundControlQmlGlobal instead of Vehicle (available all the time)

Move all airmap related stuff to its own directory

Replacement code to speed up work on the map and fighting mistake 'manual control lost' when connected joystick with armed UAV

This allows for better multi-vehicle testing

* Map type now set from General settings
* No map type control in maps

Instead of hardcoded "QGroundContorl" strings

Convert bool settings to SettingsFact

* Holds all the settings for the app
* Allows core plugin to override default values

Made QGCCorePlugin derive from QGCToolBox and expose everything through the same mechanism as everything else.

This makes it available on mobile builds

_finalize methods need information which is not available if all you
have is a mavlink_message_t

Move battery.percentRemainingAnnounce to Qml Global

The static Fact was causes problems with Qml