Add network ids to /protocols endpoint

[tboeckmann]

Is your feature request related to a problem? Please describe.
In order to support substrate, the /protocols endpoint should return network ID with the network name in the response for each protocol.

Describe the solution you'd like
Upgrade the existing response to include the name & id fields as strings. Empty id values should be returned as empty strings.

E.g.:

[
  {
    "name": "string",
    "networks": [
      // "string"    <-- previous value
      { "name": "string", "id": "string" }
    ]
  }
]

Describe alternatives you've considered

Additional context

[tboeckmann]

See here for reference to Network IDs in substrate:
paritytech/substrate@cf98501#diff-a40465c5924214464e991fe6c9deb541R327
&
paritytech/substrate#3147

[robdefeo]

closed by #401