ToolStrip rearchitecture for encapsulation and customization

Rework Fly View into separate layers which can be customized at each layer.

More FlyView encasulation. Make QGCPipOverlay completely self contained

More work on encapsulation in Fly View

Fly View: Move business logic inside controls

Major rework to support terrain profile display and terrain collision reporting

Fix display of Continue Mission/Change Alt after Pause

Mavlink terrain protocol support

Put back ToolStrip titles which were mysteriously removed

added function to FlightView to show the checklist if switching views from a view other than FlightView and if checklist should be shown

Makes more sense for it to be in VideoStreamer as it takes care of managing
the video streams.

Fix sizing/scrolling

Use parsebin for automatic stream demuxing and parsing; Automatically insert rtpjitterbuffer for RTP streams to avoid video stuttering

Switch to decodebin and use decoder with highest rank; Use GL context provided by qmlglsink; Fix JNI code for AndroidMedia initialization

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Fix video initialization - VideoReceiver did not start because sink was not created because videoBackgroundComponent was not loaded on startup if video was disabled