Use QGCCombBox with alternateText for better understanding of the ability to click on these indicators

Update all files that use a QML Menu item to QtQuick.Controls 2.4 to solve the issue of a menu showing up in random places on Android.

Handles branding logo visibility according to available space.

Restore QGC to its normal UI layout (buttons on toolbar)

Windows fixes

Fixed flight widget position.

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

Fix toolbar logo visibility

TODO: Improve the experience

Prevent clicks going through top level items

Show the link indicator in the tool bar if two or more links are connected and at least one of them is a high latency link.
Show in the link indicator if a link is inactive.

- Improve function names
- For notifications of an active link change only show the priority keyword if multiple links are connected
- Use QMap instead of QList for the HeartbeatTimers
- Style improvements
- Simplify sending the MAV_CMD_CONTROL_HIGH_LATENCY command

This setting enables/disables the LinkIndicator toolbar in which the primary link can be chosen.

The LinkIndicator shows the connected links and lets the user select the priority link,