feat: bootstrap `Connection` aggregate

[nanderstabel]

Description of change

There are two important changes in this PR:

1. The previous Connection aggregate in agent_verification is merged into the AuthorizationRequest aggregate.
2. A new Connection aggregate is added to the agent_identity domain, this also means that two new endpoints are opened:
   • /connections both GET and POST: For GET additional query parameters can be added, for example: GET 'http://localhost:3033/v0/connections?did=did:example:123'
   • GET /connections/:connection_id: To query a Connection by connection_id

Note that in this PR the Connection aggregate is not that useful just yet. Once we have figured out a nice ergonomic way for different domains to 'interact' with each other, then connections can be created, or updated based on activity in the verification, issuance or holder domain.

Blocked by

• 130

Links to any relevant issues

• 125

How the change has been tested

Added unit tests and added Postman Collection Requests

Definition of Done checklist

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• [x] I have performed a self-review of my own code
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• [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
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[github-actions[bot]]

:tada: This PR is included in version 1.0.0-beta.4 :tada:

The release is available on GitHub release

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