User configurable reports

the plan is to pilot/QA on this on prod so I'm putting it out for code review now. I'm guessing it's easiest to review as a whole, though the commits should represent ~atomic actions.

I think it's good to merge whenever code review passes.
I tried to [kill E128](https://github.com/dimagi/commcare-hq/blob/master/.lintrc#L10), maybe it didn't stick or it hadn't gone through at this point.