refactor: Refactor `RequestUrl` to `AuthorizationRequest<E>`, add `Extension` trait

[nanderstabel]

Description of change

This PR includes several changes:

• Use of JsonValue instead of serde_json::Value
• Refactor of AuthorizationRequest (in oid4vc-core/src/authorization_request.rs) which means the previous awkward RequestUrl is deprecated. Possible variations of AuthorizationRequest are now: AuthorizationRequest<ByValue>, AuthorizationRequest<Object>, AuthorizationRequest<Object<SIOPv2>>, and AuthorizationRequest<Object<OID4VP>>.
• A new Extension trait (defined in oid4vc-core/src/openid4vc_extension.rs), which allows for a clearer distinction between oid4vc-core, siopv2 and oid4vp. The core part of both AuthorizationRequest and AuthorizationResponse or now moved to the oid4vc-core crate.
• ClientMetadata and Scope are moved to oid4vc-core as well now.
• Upgraded ed25519_dalek dev-dependency.
• Temporary removed the outdated iota DID method.

Links to any relevant issues

n/a

How the change has been tested

Several unit test added/modified

Definition of Done checklist

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

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

[nanderstabel]

Closing this PR in favor of #60 which has same functionality but cleaner git history