Update raw data model

[weaverba137]

This PR closes #92.

So far I have created placeholder files for all raw data FITS files based on 2022-01 files. A few of the files need to be merged with their older versions. I'm opening this PR to get a discussion going on these files.

Help Wanted in filling in the top level summaries in some cases, describing HDUs, and checking that older data model files can be merged with more modern descriptions.

There are four files that need to be merged:

• desi-EXPID.rst and desi.rst
• focus-EXPID.rst and focus.rst
• guide-EXPID.rst and guide.rst
• sky-EXPID.rst and sky.rst

In all cases the -EXPID.rst version represents the model from several years ago, while the "bare" version is based on contemporary files.

[coveralls]

Coverage remained the same at 96.412% when pulling 118c7cf on update-raw-data into d7159e3 on main.

[weaverba137]

The desi-EXPID.rst file turned out to be relatively easy to merge. I'll likely need some expert help with other files.

[weaverba137]

@sbailey, I've merged the other files. Ready for review.