Resolve "Add three read sampling schemes to OCA rules 1010, CP, dark sampling"

Closes #113 (closed).

This adds READMODE to all templates and raw data, propagates it to the MasterDark, MasterFlat and Detrend, and uses it in the OCA rules to select the right Darks and Flats for each readout mode.

Perhaps the easiest way to review this would be to look at augment_backward_chaining.py