WIP: Add ability to schedule GEO sats; Add maximal observation duration

GEO sats:

Maximal duration (missing whitespace in screenshot already fixed):

Tested locally.

• Schedule GEO observations (note: selected time range must be <30min)
• Schedule overlapping GEO obs (add ISS obs, then schedule GEO)
• Tried to schedule GEO obs >30 min (should return the error message above)

edit: WIP, as it is based on !641 (merged) .

edit2: WIP, as it is based on !658 (merged) and local test wasn't re-run yet.

edit3: Local Tests re-run.

edit4: Updated screenshots.