SAK-24180

Fix the missing counts in the admin UI. Switch the count computation from pulling
in all the content items and an in-CPU loop and switching to 
LEFT JOINS and COUNT(DISTINCT..) to scale better.



git-svn-id: https://source.sakaiproject.org/svn/basiclti/trunk@132601 66ffb92e-73f9-0310-93c1-f5514f145a0a