Add created by property for groups

Track hours on this issue to: http://dev.nysenate.gov/issues/5684
1. Add created_id column to civicrm_group table (to store civicrm_contact.id)
2. Set created_id value when group is created
3. Add sortable 'Created By' column to Manage Groups selector (between ID and Description). Column contains contact sort_name linked to contact summary.
4. Add 'Created By' search criteria to Find Groups form on that page.
5. Add 'Created By' readonly display field to Group Settings form when action = update (below group Name).