add support for did:web

[andrea-dintino]

I guess this would require also updating the Docker image on https://github.com/decentralized-identity/universal-resolver

[matteo-cristino]

What do you mean support? Should we both create and resolve that did? I think that is out of the scope of this project since this is related to our DID. To create or resolve other DID we should use respectively universal registrar and universal resolver