PX4 multi-battery setup

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

Adding missing qgcView to QGCMapPolygonVisuals instance in SurveyMapVisual.qml

Instead of hardcoded "QGroundContorl" strings

- Fix imports to support 5.7
- Move properties to correct location

* Add volt/amp calculators

* Correct amps per volt calculation

UI Tweaks for all mobile platforms.

* PX4: Deal properly with optional components

* RC map UI: Offer better defaults and user guidance

all calls to qsTr are done, if I didn't forget anything,
on the PX4 QML files.
Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>

Add scroll height indicators to Flickable