Support Service information endpoints in DID documents

[psotres]

DIDs will probably need to support Services to list public DataSpace related endpoints. Still, they might need to be updated after initial DID generation, so updates of DID document should be also supported.

See example of EDC DIDs:

{
  "id": "did:web:did-server:company1",
  "@context": [
    "https://www.w3.org/ns/did/v1",
    {
      "@base": "did:web:did-server:company1"
    }
  ],
  "service": [
    {
      "id": "#identity-hub-url",
      "type": "IdentityHub",
      "serviceEndpoint": "http://company1:7171/api/identity/identity-hub"
    },
    {
      "id": "#dsp-url",
      "type": "DSPMessaging",
      "serviceEndpoint": "http://company1:8282/api/dsp"
    },
    {
      "id": "#self-description-url",
      "type": "SelfDescription",
      "serviceEndpoint": "http://company1:7171/api/identity/identity-hub/self-description"
    }
  ],
  "verificationMethod": [
    {
      "id": "#company1-key-1",
      "controller": "",
      "type": "EcdsaSecp256k1VerificationKey2019",
      "publicKeyJwk": {
        "kty": "EC",
        "kid": "yy_d7lbBzYC8EC0NDdX-r4fyf9SLsl8ZzviM5EzWRS4",
        "crv": "P-256",
        "x": "WohdFPABfA3tv5jYqR_qPEpZDRjSjQaoh4PlHBLemlY",
        "y": "c6eeeLzV0m4HEioTUL59yREOqILPxpx5m-MNCTDO6nI"
      }
    }
  ],
  "authentication": [
    "#company1-key-1"
  ]
}