Create distribution structures from FEEPS data products

[jameswilburlewis]

It should be possible to generate moments, 2d slices, etc from FEEPS data, but we don't yet have a way to create the needed distribution structures from the available data products. (For example, combining the separate telescopes into a single structure with calibrated data by angular and energy bins).

We will probably need to get the FEEPS team involved in this effort, to fill any gaps in the available products, or our understanding of them.