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

Map gimbal controls
Keep track of gimbal position within Vehicle

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>

Q_ENUMS is deprecated and should not be usued.
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.

Added (UI) support for vehicles exposing more than one camera.

Split save mission to Json file in two so you have the option to saving it to a file or to a QByteArray Json blob.
Virtualize all camera functions to allow deeper access.

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

Handle survey mode state