Add new facility mode for reporting rate report

![screenshot 2014-12-04 12 33 01](https://cloud.githubusercontent.com/assets/152134/5303289/1f1d18ca-7bb6-11e4-872d-c100bd3871c4.png)

https://docs.google.com/a/dimagi.com/document/d/1WkTqsdy4aC-gF1j0mGUCs7p_Y41jK5LGq0kxDJWF_hQ/edit
it's just a django model for form metadata so should be pretty straightforward: https://github.com/dimagi/commcare-hq/blob/master/corehq/apps/sofabed/models.py#L51