Also additional major Mission usability changes

Also remove concept of “interactive” since it is no longer needed

Also show QGC position on map

Instead us a Toolbox concept which hangs off of QGCApplication

They were causing variable scoping conflicts. This in turn caused the
widget to not update. Active property is not needed since the handling
of active/inactive vehicle is handled outside of the control

Updated existing icon and added a new one for when things have changed.