Make VC accept any kind of schema. Not just hypersign schema.

[Vishwas1]

We should also support :

  "@context": ["https://www.w3.org/2018/credentials/v1", "https://schema.org/"]
  "id": "http://example.edu/credentials/332",
  "type": ["VerifiableCredential", "IdentityCredential"],
  "issuer": "https://example.edu/issuers/4",
  "issuanceDate": "2017-02-24T19:73:24Z",
  "credentialSubject": {
    "name": "J. Doe",
    "address": {
      "streetAddress": "10 Rue de Chose",
      "postalCode": "98052",
      "addressLocality": "Paris",
      "addressCountry": "FR"
    },
    "birthDate": "1989-03-15"
    ...
  },
  "proof": { 

 }
}