Initial commit of the new method "prayer"

The new method is a "clean-room" implementation of the prayer times
and qibla direction calculations. This new implementation uses
simpler but approximate methods. This should make the code much
simpler and easier to maintain. The impact on accuracy is still
to be determined. Please NOTE that this is still WIP and far from
being complete
We should also include fajrTomorrow. A common use-case is to show how long until the next prayer and after Isha the next prayer is the following fajr. Instead of doing a separate calculation it would be more convenient to include it in the same prayer_times struct.