Make obfsproxy daemon bind to specific address rather than 0.0.0.0

If obfsproxy is spawned alongside eip service, make it listen to
the gateway_adress IP. If obfsproxy is running standalone listen
to ip_address.
Introduce eip-service-2.json to add values for obfsproxy
Make web_app serve eip-service-2.json, with obfsproxy details
Let eip-service-2.json pick obfsproxy details from vpn nodes too.

When obfsproxy is deployed alongside eip service, gateway address
will be used. If standalone, ip_address will be used.
In eip_service_2 definition, move gateways from array to hash
Remove serial and version from eip_service_2 definition