Protobuf contracts

[lipchev]

I just wanted to get your thoughts on the potential addition of a project packaging .proto files + mapping extensions. I haven't done any meaningful work on this yet, and things have probably changed a bit since the last time I checked the online articles about how to package and share contracts, but yeah I'm sure the AI would be able to figure it out...

The question is do we want to entangle ourselves with another serialization schema, before the v6 release (or ever).