QGCCameraControl::storageFreeStr(): use QGCMapEngine::storageFreeSizeToString()

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

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

Keep track of recording time if camera doesn't provide it.
Make sure camera info is received (if camera ACKs the request)
Keep track of camera's heartbeat. Remove camera if not heard from after a while.
Update MAVLink

Add "known" parameters to camera controller.

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

Making sure the commands are sent to the camera's actual component ID rather than a hardcoded constant.

Move  MAV_PARAM_TYPE to  MAV_PARAM_EXT_TYPE as we're now using the proper MAVLink version.

Handle survey mode state

Ignore Fact index if there are no enums (avoid adding an "Unknown" entry)
Add function to convert and clamp a (Fact) value.

Adding some more logging

Allow plugin to validate parameter setting.