feat: add support for linked verifiable presentations

[nanderstabel]

Description of change

Adds (dynamic) Linked Verifiable Presentation support to UniCore

Links to any relevant issues

• Add support for Linked Verifiable Presentations #86

How the change has been tested

The updated Postman Collection can be used to test this added functionality manually:

make sure did web and domain linkage are enabled (and preferred) in the config (or .env) file:

did_methods:
  did_web:
    preferred: true
    enabled: true
 # make sure did:iota:rms is not enabled
  did_iota_rms:
    enabled: false

domain_linkage_enabled: true

Issuance:

1. execute /Issuance/temp_thuiswinkel_credential
2. execute /Issuance/offers_send

Holder:
3. execute Holder/offers (the Offer sent by the Issuer should be returned in the Response)
4. execute Holder/offers_accept
5. execute Holder/credentials (copy the credential_id value in the response)
6. execute POST Holder/presentations (paste the credential_id value in the array in the Request Body, copy the presentation_id value that is returned in the Response)

Identity:
7. execute Identity/linked-vp (paste the presentation_id value in the array in the Request Body

To check whether the linked VP was successfully added, execute .well-known/did:web. You should see that two services are added to the Document, one of them has the LinkedVerifiablePresentation type. The serviceEndpoint should be pointing at the endpoint where the Linked VP is hosted

Definition of Done checklist

Add an x to the boxes that are relevant to your changes.

• I have followed the contribution guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have successfully tested this change in a docker environment