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

The Url in custom command widget has been moved to
https://docs.qgroundcontrol.com/en/app_menu/custom_command_widget.html

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

This reverts commit 7e6588f6.

Adding missing qgcView to QGCMapPolygonVisuals instance in SurveyMapVisual.qml

_finalize methods need information which is not available if all you
have is a mavlink_message_t

Also report the current transfer rate in the currently downloading status to help expose regressions in performance.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>