Write dummy image receiver code

[pizzalemon]

Writing this as an issue so I don't forget about it.

At some point, the dummy image receiver code got deleted. Unfortunately the old code was intertwined with the now defunct Interop, so it can't be directly copy-pasted into the current code base. Just has to be rewritten for the current code as some point. This is needed to populate the submissions page for development purposes.

If I remember I'll add a link to the old code here.

[pizzalemon]

Link to the old code:

GroundStation/server/handlers/image.py

Line 53 in 1852d64

def process_image(self, image):