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

Get rid of QGCView, QGCViewPanel and FactPanel. All messages and dialogs are now handled in the root window.

Limit all queries to areas smaller than 500km^2. If an area of interest is greater, clip to 500km^2 centered on current ROI's center.
Removed the identifier "Airmap" from error messages coming from Airmap.
Added a clipping function to QGCGeoBoundingCube (clip polygon to given area)

More clang warnings cleanup

Make the choice of using a personal key persistent. This will allow to toggle between personal and hardcoded key. Otherwise you would need to clear your personal key each time you want to use the hardcoded one.

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).

Add message asking user confirmation to end a flight

Remove delete flights and add "End" active flight instead
Work on flight geometry (flight list)

Flight management with date range, delete flights.

All settings wired and persistent
Cleanup non Airmap builds