er15 fixes

 * new cert for gstlalcbc user
 * new default values for gunicorn configuration
 * remove `Labels:` row from superevent table in public-facing view (@roberto.depietri)
 * add a link to return to object page from files page
 * relax annotation throttle for authorized users
 * lots of pre-O4 cert changes
 * test change to improve performance of public view