[Feature]: Merge @retoph refactored codebase

[PBechon]

@rettoph have completely re-written kerbal simpit, mainly for breaking the core simpit protocol into its own .net standard library. This refactoring have been used by himself but not tested by a big number of players. It should be easier to start from here for a new implementation (for instance KSA ...).

Core Simpit: - Includes Unity hooks if needed, but can just as easily be used in any c# app KSP Simpit: - Integrates KSP specific logic and messages

Arduino Core Simpit Arduino KSP Simpit

No decision has been made to support this refactoring of not, this issue is created to discuss and keep track of this refactoring.