files: add session recording flag
    
    If session recording is configured for a group the NSS ans PAM
    responder rely on a attribute in the cache set by the backend to
    determine is session recording is configured for the user or not. This
    flag is typically set during the initgroups request.
    
    Since the files provider does not have a dedicated initgroups request
    the attribute must be set otherwise. This patch sets is for all users
    after the files are reloaded.
    
    Related to https://pagure.io/SSSD/sssd/issue/3855
    
    Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>