Precalculate passes
Once #419 (closed) has landed we need to implement a mechanism to populate the precalculated passes model. When new TLEs are fetched we should calculate all passes of that satellite on all stations and store them. The time window should be now() (the time of fetching) +48hours. Mean TLE update time according to Celestrak is 1.54 days.
One consideration is how to deal with new fetching of TLEs when existing calculations are in place. I propose upon fetching a new TLE, we delete all >now() predictions and calculate +48 hours.