Add ExchangeSupervisorActor

**Description** Add ExchangeSupervisorActor without the handling of the failure cases, which will be handled by a new actor which is out of scope for this PR
**Testing** Tests added, tests pass
**Coverage**

- ExchangeSupervisorActor: 100%
- InitializedExchangeSupervisorActor: 93.40%
- DefaultHandshakeActor: 100%
- InitializedHandshake: 100%
Discussed offline: these messages have a guaranteed delivery since they are sent to in-memory actors. We agreed that it is not worth having timeouts for these cases.