XDEBUG_CONFIG=remote_host=10.254.254.254 is redundant

> DNS name `docker.for.mac.host.internal` shoud be used instead of `docker.for.mac.localhost` `(still valid) for host resolution from containers, since since there is an RFC banning the use of subdomains of localhost (See https://tools.ietf.org/html/draft-west-let-localhost-be-localhost-06).