KNL-1011 - Allow control of lazy loading in Site copying and caching

 * Add collection getters to BaseSite that can avoid fetching
 * Call the lazy getters for copy construction (in set())
 * Call the lazy getters from SiteCacheImpl when making copies
   for cache put notification



git-svn-id: https://source.sakaiproject.org/svn/kernel/branches/KNL-1011@118313 66ffb92e-73f9-0310-93c1-f5514f145a0a