Replace Buf Remote Plugins with local vendored plugins

Buf is the best tool to manage protobufs. One of the biggest pain points of protobuf is the management of protoc plugins. You need to manage them, and make them available to other engineers working on the same repository/project. Versions need to be centrally managed, code generation must produce the same result, no matter if it happens on an engineer A or B’s machine, or in CI. This becomes even more challenging, as protoc plugins are written in different programming languages. Read more