There are many ways of iterating over lists in C++/Qt.
In the specific case of QStrings, it is known [1] that using
foreach with const references avoids the creation of new
QString objects in each iteration, reducing the time consumed
by the loops.

[1] https://blog.qt.io/blog/2009/01/23/iterating-efficiently/Signed-off-by: Anselmo L. S. Melo <anselmo.melo@intel.com>

Also turn on MavlinkLogTest

Instead us a Toolbox concept which hangs off of QGCApplication

Too unstable for CI at the moment

Was failing due to large log output from incorrectly named
MockLinkLogVerbose.

- select active vehicle
- arm/disarm
- select flight mode

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

Also many LinkManager API changes to further isolate all link
management inside LinkManager.

Moving methods from MainWindow to QGCApplication so that more things
can run without a window. Helpful for testing.

So no need for connect window close test here