Prepare for latest VC HTTP API tests

[clehner]

Spruce VC-HTTP-API Test Report (demo server): https://w3c-ccg.github.io/vc-http-api/test-suite/spruce/

• Support Revocation List 2020 and updateCredentialStatus (Optional)
• Support BbsBlsSignature2020, BbsBlsSignatureProof2020 and deriveCredential (Optional)
• Add Citizenship and Vaccination vocab contexts to ssi: Add Citizenship and Vaccination contexts ssi#118
• Add Traceability context to ssi: Add Traceability context ssi#135
  • Debug test case verification errors: Preserve time zone offsets in credentials ssi#233
• Validate verificationMethod option in issueCredential: Use URI for verificationMethod option #184
• Use updated endpoint names in didkit-http: Use vc-http-api controller pattern #102
• Support DID Document of did:web:vc.transmute.world(issuer of verifiableCredentials/case-5.json)
  • Allow relative DID URLs in DID documents: Support relative DID URLs ssi#119
  • Support verification method defined in DID document publicKey array: Improve DID URL dereferencing for verification methods ssi#128
  • Support publicKeyBase58 for Ed25519Signature2018: Support publicKeyBase58 for Ed25519Signature2018 ssi#121
• Triage remaining failing tests. Done: no other known failures.
• Host public-facing didkit-http instance
• PR adding Spruce/DIDKit to vc-http-api-test-server: Add Spruce config w3c-ccg/vc-api#166
• Test in DIDKit's CI: Test with vc-http-api 0.0.2 test suite #104