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.
Suggestion: `assert spec.property_path, spec.property_name` will make debugging easier if this assertion ever fails.

Also four lines above: `assert not spec.property_path, spec.property_name`