adding new user management feature

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@174962 a5903396-d722-0410-b921-86c7d4935375
adding user-manager module

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@174963 a5903396-d722-0410-b921-86c7d4935375