Remove telemetry heartbeats

Add support for Linux and experimenting with settings (there are "set" but no "get" options for them though)

On desktop (Ethernet connection), the ground unit pushes UDP directly, which makes the use of an actual "Link" not possible. Instead, I've moved all of Taisync support to a "manager" owned by QGCToolbox.
Added a Taisync settings with some basics already wired and running.

Add support for Orbit flight mode

Show Orbit center from telemetry

Fix AutoLoad not sending GeoFence or Rally Points to vehicle

Fix Rally Point loading

Fix handling of dirty bit when home position changes from vehicle side

Fix rotation

Fix bit check

Fix category change signalling.

Three components for better testing

Fix support for single vehicle coming and going

Show orbit telemetry status on map

Remove incorrect zorder

Larger arrow size

* Add support for showing rotation on QGCMapCircle.
* Support rotation change for Orbit

Fix connections to offline vehicle