Need Test Data

We need data to test and develop/benchmark against. I have been using the "apo05" M dwarf data for my test reductions. We need example data from different kinds of instruments/science/wavelengths.

Should this (potentially large) amount of data live in the new `specreduce_data` repo?

I would propose test/example data should at least include:
- all the data to fully reduce the science spectrum end to end, including flats/biases/darks/arcs/flux standard
- the combined or master cals (flat/bias/etc) so we can test individual methods of `specreduce` without worrying about changes to `ccdproc`
- a fully reduced spectrum that can be read in as a `Spectrum1D` object
- a short README describing the data, the reduction workflow for the observation (i.e. is there anything unusual or special we're need to know or ensure we capture with the `specreduce` machinery), and how the benchmark reduction was produced (IRAF/IDL/etc)

An example reduction script or notebook using `specreduce` would also be good, but might not be possible for all data if certain machinery hasn't been built yet.

No implementation files or tests are named; start by determining whether the proposed specreduce_data repository should hold the datasets. Define a representative set of end-to-end and calibration data, a reduced Spectrum1D example, and README documentation covering the workflow, unusual details, and benchmark provenance; an example specreduce script or notebook is an optional goal.

Written by the indexing model from the issue text.