Make goji config-less

[byxorna]

Perhaps theres a way we can make goji discover its config from environment variables set on applications in marathon, instead of needing to specify each app in the config json?

Perhaps setting GOJI_NAME=myapp in an app could be discovered by goji, and automatically create the myapp.* vhost/acl rule? Just spitballing. How does this work with the options hash? TCP services?

[byxorna]

https://mesosphere.github.io/marathon/docs/rest-api.html#labels-object-of-string-values could be used to mark apps as exposed via goji or not. I.e. "GOJI_VHOST"="myapp.iata.company.net". GOJI_DISCOVER=true