Restructure toolbar to make it Flickable

Use showIndicator property to set correct visibility in loader. This leads to correct spacing on all platforms.

Change to combobox

Fix spacing

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.