OO-3489, OO-3492, OO-3493, OO-3494, OO-3496, OO-3497: infrastructure to export user data, export  portraits, notes, personal folder, calendars, subscriptions, delete calendars after usser deletion

OO-622,CL-225: remove username from GUI in place where is not really needed and students can see it. Mark others place with //TODO username where it need more works and/or the username is only visible by author/coach/admin... Additional fix the setup sql for MySQL (index too long).

OO-592: break direct dependency to UserDataDeletable and DeletableGroupData interfaces, remove unused spring configuration files...

OO-291: first step: move business gourp manager to a business group service, remove dependency to the context...

--HG--
branch : bps