Move ArduPilot preflight check handling to generic QGC

Some crazy shit in UAS.cc was using an array of 256 bytes to handle received messages and mapping them to components. Well, any message ID over 255 would cause a buffer overrun.

* Some code moved to Vehicle

This reverts commit ae976049ca7b4818616e6b8be07a028fc7dfc26f.

Removed incorrect Vehicle.altitudeWGS84

Instead us a Toolbox concept which hangs off of QGCApplication

- Delete all old map code

- New MissionManager
- Plumb MissionManager through MissionEditor
- Mission Editor supports get/set

Plus lots of other cleanup

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

- 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