Custom build override for stable version check no longer needed

Support GuidedActionsController logging

Add new Help page under Settings

All settings wired and persistent
Cleanup non Airmap builds

Clarify the title of the "Video Stream" panel (instead of just "Video")

Also rename QmlPageInfo to QmlComponentInfo to cover more use cases

Also plugin'ize intrument panel PageView pages

Hide "Save Path" as it breaks the UI in General Settings.

Also added Vehicle.flightTime to default setup

* Holds all the settings for the app
* Allows core plugin to override default values

Made QGCCorePlugin derive from QGCToolBox and expose everything through the same mechanism as everything else.