add randev decoder

Hello, This is the decoder for the Randev satellite (Norad ID 52898) for the creation of it's dashboard.

This was tested and seem to work. However, the frame_decode.py script could not serialize with json.dumps as I have Enums. I tested the scripts by replacing the json.dumps with a simple str conversion. I do not know if I should remove the Enums, or keep them as is as we can see on few reference .ksy files presenting the same problem (Equisat, and Irvine).

Signed-off-by: Marin Mikaël marin.mikael@kaist.ac.kr