Document the did:prism resolver and universal resolver

[FabioPinheiro]

Add documentation about:

• different the resolvers

• the endpoint on the could agent

• the current architecture of uniresolver for did:prism https://dev.uniresolver.io/

• https://github.com/FabioPinheiro/universal-resolver

• Add support for prism did method decentralized-identity/universal-resolver#440

[robertocarvajal]

We noticed the universal resolver says our driver is partially compliant which I think is a mistake due to one of the test DIDs being deactivated.

@FabioPinheiro please take a look at this reported issue since you might know better whats going on

hyperledger-identus/.github#136