completing the pluggable authenticator support for SCIM endpoints

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@176682 a5903396-d722-0410-b921-86c7d4935375
adding SCIM authenticators config element to identity.xml

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@176683 a5903396-d722-0410-b921-86c7d4935375