126058 jkaabimofrad: ACE-5001: Added a utility class to calculate the number of days between the start and end dates, so we could have a single source when dealing with such functionality. Also, changed the RepoUsageComponentImpl class to use this util class.
git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/BRANCHES/DEV/5.2.N/root@126098 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261
