Admin console stats

Functionality from oo-stats is needed in admin-console.

I broker oo-stats into the script that accepts params and formats output, and a library in the form of a Rails model (Admin::Stats). This is the first entry in what will someday become the admin library for shared administrative code.

Only noticeable difference to oo-stats users should be that results data previously provided as arrays of hashes are now also provided as hashes of hashes, which will make serialized representations either a little larger or a lot larger.