Add plumbing for rollup creation and deletion through soda fountain.

Soda fountain translates the column names on the rollup on the way through to
data coordinator.  Currently supports PUT and DELETE, GET is not yet fully
implemented.
I can add a general DataCoordinatorClient.UpsertUserError(_, _) or even DataCoordinatorClient.Result case to ensure a match on all cases, but I'm not sure what I'd do there other than throw an exception or create new Result type... which seems like it should be higher level logic somewhere.  I did have a UpsertUserError case in there, but couldn't easily figure out something clean to do in it.  deleteRollup has the same issue; it handles the "expected" not found case but just blows out on the unexpected case.

Result is a bit of an oddly typed thing to start with, since only some functions can return some Results.

Error handling in soda fountain needs a big revamp overall, this change is following the existing patterns.  I'm not sure how much we want to invest in improving it as part of this.