[Task] Implement the IOTA DIDComm Connection protocol

[PhilippGackstatter]

Description

Implement the IOTA DIDComm Connection protocol using the actor.

Motivation

Add DIDComm support for the actor in a specified way.

Resources

https://wiki.iota.org/identity.rs/specs/didcomm/protocols/connection

To-do list

Create a task-specific to-do list. Please link PRs that match the To-do list item behind the item after it has been submitted.

• [ ] Implement #841.
• [ ] Implement the IOTA DIDComm protocol in the actor.

Change checklist

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• [ ] The feature or fix is implemented in Rust and across all bindings whereas possible.
• [ ] The feature or fix has sufficient testing coverage
• [ ] All tests and examples build and run locally as expected
• [ ] Every piece of code has been document according to the documentation guidelines.
• [ ] If conceptual documentation (mdbook) and examples highlighting the feature exist, they are properly updated.
• [ ] If the feature is not currently documented, a documentation task Issue has been opened to address this.