All MavManager functionality now in Vehicle

- Moved all MavManager functionality to Vehicle
- Updated all code to use Vehicle instead of MavManager
- Removed MavManager

Switch to Development 2.8

Restructuring flight map code

Add vehicle indicator to flight display

fix global position display in UAS widget

Signed-off-by: kai <kai@uav-flightresearch.com>

UASManager -> HomePositionManager

Revert "set QGC version from git"

New MultiVehicleManager, Vehicle objects

set QGC version from git

QGC bugfixes 

- MultiVehicleManager is a Qml friendly replacement for UASManager
- Vehicle is a replacement for both UAS and AutoPilotPlugin

New FirmwarePlugin support

This can only come from the heartbeat

- FirmwarePlugin is the new place for code which is specific to
firmware flight stack
- FirmwarePlugin currently supports flight mode apis
- Modify code to use new FirmwarePlugin support