CRMI cleanup

There are a bunch of unused fields on the CRMI. Some of them I don't even know what they were supposed to do, some of them I can tell what they were supposed to do but they don't actually do it.
`SCRMI.register_from_catalog` does appear to still be used in a template in the studentclassregmodule, but that hasn't been set to `True` since Splash 2011 in MIT's database.  If that's true elsewhere as well, we may want to remove it entirely.  If not, it may be worth leaving a comment to the effect that it's now useless, or making a new issue.