Multi-Vehicle Start/Pause Fixes

* Added support for sat count to Sensors check control

* QGCCheckListItem -> PreFlightCheckButton
* CheckList -> PreFlightCheckList

Automated preflight checklist: Initial commit. Note that this requires an autopilot firmware that writes the respective health flags in the SYS_STATUS mavlink message

Signed-off-by: Patrick J.P <patrickelectric@gmail.com>

Allow plugins to define a left placement for its custom flight widget.
When placed on the left, the action tool strip is placed on the right side.

- popup don't work with map
- improve popup visible logic
Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

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

For whatever reason, showing the dialog through a function causes a crash in QML (undebugable--new word!)

Internet available now has a signal

- Don't allow goto click while other guided ui is visible
- Use NoMouseThroughRectangle for guided ui popups
- Better visuals for goto indicator in map