Attach node's name to scramblesuit password and port secrets

This makes every node with obfsproxy service have unique port and
password for scramblesuit pluggable transport.
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
/1/configs.json list service definition files by version

Introduces configs.json which list available service definition
files by version. Feature #5704