Support ssl reverse proxy client cert auth mode.


git-svn-id: https://svn.calendarserver.org/repository/calendarserver@14175 e27351fd-9f3e-4f54-a53b-843176b1656c
Add basic freebusy-URL test.


git-svn-id: https://svn.calendarserver.org/repository/calendarserver@14176 e27351fd-9f3e-4f54-a53b-843176b1656c
Fix freebusy-URL.


git-svn-id: https://svn.calendarserver.org/repository/calendarserver@14177 e27351fd-9f3e-4f54-a53b-843176b1656c