Consistent service request list and details pages

This changes the following:
* service request details page: "Date Approved/Denied" ->
  "Approved/Denied on"
* service request list: adds "Approved/Denied By" column

https://bugzilla.redhat.com/show_bug.cgi?id=1138367
Merge pull request #695 from mzazrivec/fix_request_list_details

Consistent service request list and details pages