Change VideoManager::grabImage to automatically generate file name

The receiver should not touch the old videos folder, it's not
the responsible class for that.

Makes more sense for it to be in VideoStreamer as it takes care of managing
the video streams.

Switch to decodebin and use decoder with highest rank; Use GL context provided by qmlglsink; Fix JNI code for AndroidMedia initialization

Updated MAVLink to handle video stream types (auto discovery)

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

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

- Added menu options to select new mode as well as new settings and defaults

Adding mux GStreamer plugin libraries to Android (to enable video recording on Android)
Adding an option to limit the amount to disk used for saving videos
Adding an option to show/hide the REC button (allowing plugins to handle the recording in their own way)
Adding simple frame grab to file

For Video Streaming usecase, QGroundControl doesnt support changing of
Video Source or URI settings. Restart of QGroundControl application was
required for the changes to get applied. The issue is now resolved by
restarting the video receiver pipeline with new video source/setting.
Signed-off-by: lbegani <lalit.kumar.begani@intel.com>