10. userportal, webadmin: Add authentication filter

This patch adds the authentication filter to the GUI. This doesn't
currently have any effect, as this filter does nothing if the principal
isn't available in the HTTP request. It will have an effect only if at
least one negotiating authenticator is manually configured for the
application

Change-Id: I69d05f71c76bde5cf8ff07df79f212eda2cdc7f5
Signed-off-by: Juan Hernandez <juan.hernandez@redhat.com>
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>