Set Cache-control on all generated pages, centralize in Endpoint
    
    See "Bindings for the OASIS Security Assertion Markup Language (SAML)
    V2.0" section 3.2.3.2.
    
    https://fedorahosted.org/ipsilon/ticket/7
    
    Signed-off-by: Rob Crittenden <rcritten@redhat.com>
    Reviewed-by: Nathan Kinder <nkinder@redhat.com>