add surveysim+desisurvey output files to desidatamodel

[sbailey]

Running the surveysim+desisurvey tutorial generates many files, which are described at a high level in the tutorial documentation.

Add details about these files to desidatamodel . Distinguish between which files are specific to the simulations vs. which ones will be generated as part of the survey operations. Consider splitting these into separate subdirectories so that one of those directories reflects exactly what we expect real survey operations to produce.

While doing this, identify files that are written by surveysim but are used by real operations and open tickets for writing the code for real operations. e.g. IIUC, progress.fits (currently output by surveysim) mimics a custom formatted dump of the ICS opsdb, and is then used by survey planning as an input.

This ticket covers a lot of files written by desisurvey, but filing this issue against surveysim since that is the coordination wrapper.