devilry_examiner: Use a table instead of row for rowlisting - renamed to infolistingtable.

This is because rows and columns are for layout, and changing their
margins and paddins messes up the entire layout. Tables work well:

- We can use the default bootstrap styles.
- The columns are organizes fairly well by browsers by default.
devilry_examiner.singlegroupoverview: Use infolistingtable.
devilry_examiner.dashboard: Use infolistingtable.