FW Landing Pattern: Support for stop photo/video. Plus item unit test.

Fix xcode project and restore LaunchImage
Cleanup unused icons

Fix xcode project and restore LaunchImage
Cleanup unused icons

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Add the HeartbeatTimer class to track a single heartbeat for a single link.
For every new received heartbeat an instance of the class is created.
Every instance emits a signal if it timed out or the timer is restarted.
Each vehicle then decides based on all different signals which link is the
priority link.

The build system will look for src/Airmap/Airmap_api_key.h
If it find is, it will used the provided API key and client ID for Airmap.
That file should provide two strings:
static const char* kAirmapAPIKey = "key data";
static const char* kAirmapClientID = "id data";

Local builds, without these will have no Airmap support by default (users can always enter their own within the Airmap settings panel).

It builds clean but the resources still get messed up (loads true qml files instead of dummy ones, and it crashes...)

Make all argument to AirMap queries based on what the screen shows (bounding rectangle and/or radius), respecting the limits imposed by AirMap.

Moved flight planning away from "Flight Management" to its own class. Planning does not need a connected vehicle.

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

Break apart string of classes into their own files as all in one file became unwieldy
Expose Airspace data in a QML ready format
Split global Airspace from AirMap (Only now I figured out the reason for the pure virtual root classes)
Refactored a bunch of things to make it consistent and/or obvious

Move all airmap related stuff to its own directory

which is now a shared library