Data model for the exposure and tile qa files

[araichoor]

This PR addresses #114.
It modifies the data model for the exposure-qa*fits files and the tile-qa*fits files, as both are very close.

Comments:

• it would be great if @julienguy could check the column description is correct;
• for the PETALQA extension, I ve put the definition in the exposure-qa-EXPID.rst, and refer to those in the tile-qa-TILEID-GROUPID.rst;
• I refer to the fiberassign-TILEID.rst file, which is in the not-yet-branch of the PR Datamodel for fiberassign files #103 (so the building complains the file does not exist).

A built documentation is here: https://data.desi.lbl.gov/desi/users/raichoor/tmpdir/desidatamodel_exptileqa/20220615-v0/html.

[coveralls]

Coverage remained the same at 100.0% when pulling adf170b on exptileqa into df8b1b5 on fiberassign.

[weaverba137]

The files look fine, but it appears that this assumes that #103 is already merged, when in fact it is not. Would you consider merging this branch into fiberassign rather than main?

[araichoor]

Thanks.

That is correct: I've added a comment, which refers to a file which will appear in PR #103.

I could:

• either remove that comment (no big deal; actually those infos which are propagated from fiberassign are in numerous files, and I think none mention that it comes from fiberassign);
• or proceed as you suggest (in which case, I d appreciate instructions on how to do that).

Please let me know.

[weaverba137]

Changing the branch can be done in GitHub itself. Let me test that.

[weaverba137]

@araichoor, this is ready to merge now. Do you have any further changes?

[araichoor]

Thanks a lot for handling that.
I ve no planned further change.
It would be nice to have Julien s check on the column description, but that can surely be done later, after merging.
So I think you can merge.