Adapted configuration and instantiation to ATS 7.

Deployment:
 * traffic_line has been replaced with traffic_ctl
 * access log, of squid style, is ascii instead of binary, to do so
   logging.config is generated
 * ip_allow.config is configured to allow access from any host
 * RFC 5861 (stale content on error or revalidate) is implemented with core
   instead with deprecated plugin
 * trafficserver-autoconf-port renamed to trafficserver-synthetic-port
 * proxy.config.system.mmap_max removed, as it is not used by the system anymore

Tests:
 * As Via header is not returned to the client, it is dropped from the
   tests, instead its existence in the backend is checked.
 * Promise plugin trafficserver-cache-availability.py is re enabled, as
   it is expected to work immediately.