Create interface to get stars from Gaia catalog

[wmwv]

Create a function that allows the caller to get a set of stars from Gaia.

Spatial Searches

1. One detector: get stars to a detector coverage plus a customizable buffer.
2. One FoV
3. A region in RA, Dec specified by Circle, Bounding Box

Optional: specification of magnitude range.

Returns either pandas dataframe or AstroPy Table. Your choice.
(relatedly, I'd like to standardize on one vs the other in photometry, the "dataframe" <-> parquet vs. AstroPy Table has me torn.)