Pointing-aware point source analysis

[israelmcmc]

Don't include times when a point source is behind the Earth.

This is the parent issue for multiple sub-issues since the implementation depends on whether the analysis is binned or unbinned, and modeled or unmodeled (RL).

Note: I didn't separate the unbinned case into modeled and unmodeled since the changes in the response will automatically propagate to both. In the binned case, on the other hand, we could decide to have a pointing-aware modeled analysis that works well only for a single source at a time, but RL necessarily needs to consider all location simultanously.