MPC-TLS actor refactor

[sinui0]

This PR refactors our MPC-TLS implementation to use ludi and generally have better state management, errors and logging.

Changes

• Modified Backend trait to have all async methods with only owned arguments.
• Updated tls-client for changes to backend trait.
• Refactored MpcTlsLeader and MpcTlsFollower to use ludi
• MpcTlsLeader is no longer passed directly into the tls client, instead a controller is.
• Refactored the MpcTlsError to be more opaque, concealing implementation details that shouldn't be in the API. At the same time, it provides better debugging information.
• Introduced cleaner internal states to both the leader and follower, and added state guards in numerous places to catch unexpected events.
• Introduced more explicit protocol messages between the leader and follower.
• Encapsulated encryption functionality into record_layer
• Decoupled message commitment from message decryption, to support deferred decryption in a coming PR.

[th4s]

lgtm 👍

[themighty1]

thanks, will review soon

[themighty1]

ACK, left some non-blocking comments