allow users to reuse distribution certs; migrate credentials (#2361)
allow users to reuse distribution certs; migrate credentials (#2361)

* [www] add postgres to docker compose

* [exp] [xdl] [www] store app credentials in postgres

* [tools] allow to pass local port to rethink-proxy

* [www] add credentails migration (rethink -> postgres)

* [exp] [www] allow to remove dist cert / app credentials using exp

* [www] delete temporary script

* [xdl] [exp] merge questions about reusing dist cert

* [www] use more env vars in docker-compose

* [www] add getting apns p8 key from postgres

* [www] add getting push cert from postgres

* [www] add getting/deleting android push creds from postgres

* [www] Remove accidentally committed conflict marker.

fbshipit-source-id: 1707122

exponentjs/xdl,exponentjs/xdl,exponentjs/xdl