Sidetree Spec Defines Version Endpoint

[OR13]

For example:

curl -X GET "https://staging.element.transmute.industries/element/versions" -H  "accept: application/json"

[
    {
      "name": "core",
      "version": "0.1.0"
    },
    {
      "name": "ethereum",
      "version": "0.1.0"
    },
    {
      "name": "ipfs-with-cache",
      "version": "0.1.0"
    }
  ]

[OR13]

IMO it would be better for us to return what is defined here: #886

{
  "genesisTime": 0,
  "multihashAlgorithm": 18,
  "hashAlgorithm": 5,
  "maxOperationCount": 10,
  "maxOperationSize": 200000,
  "compressionAlgorithm": "GZIP",
  "maxAnchorFileSize": 1000000,
  "maxMapFileSize": 1000000,
  "maxChunkFileSize": 1000000,
  "patches": [
    "replace",
    "add-public-keys",
    "remove-public-keys",
    "add-services",
    "remove-services",
    "ietf-json-patch"
  ],
  "signatureAlgorithms": [
    "EdDSA",
    "ES256",
    "ES256K"
  ],
  "keyAlgorithms": [
    "Ed25519",
    "P-256",
    "secp256k1"
  ]
}

[troyronda]

API spec update.