Hotel Domain with Reactor

[bartelink]

Based on Oskar Dudycz's HotelManagement sample:

• Replaces saga/bus with Process Manager
• Wired for MemoryStore and DynamoStore for now (PRs welcome to add more)
• [x] Reactor Tests
• [x] Reactor
• [x] Reactor.Integration - MemoryStore
• [x] Reactor.Integration - DynamoStore
• [x] Apply @nordfjord and @alexeyzimarev feedback
• [x] Make Outcome make sense
• [x] Review with @oskardudycz
  • should there be a version in EventSourcing.NetCore (Yes)
  • should that version also support Esdb and Mdb (Yes - the esdb stuff will be noisy, but the docker compose will make it work from the repo OOTB)
• [x] Add MessageDb wiring

See equinox-shipping for more extensive wiring