Refactored the UserProvider and AuthProvider interfaces to better separate concerns. All password tasks are now handled by AuthProvider. Also did some refactoring work on the JDBC* providers. (JM-751)

git-svn-id: http://svn.igniterealtime.org/svn/repos/wildfire/trunk@4263 b35dd754-fafc-0310-a699-88a17e54d16e