Extract order and graph validation related logic and target to develop

[sauk2]

Summary

We need to isolate the order and graph validation related code in #3 so they can be developed and tested independently of OrderManager and StateManager. This will form the base for subsequent PRs related to order. The general idea is to,

• Move all the order validation related code into a separate branch (OrderGraphValidator and associated classes)
• Use the hard types introduced as part of PR feat(types): create C++ structs for VDA5050 2.0.0 spec #6
• Make sure there is no interaction with the state logic
• Write unit tests