Type-safe Protobuf implementation

[temeddix]

Current implementation using messagepack is not so type-safe. Maybe we should provide communication with protobuf inside the template.

[temeddix]

The main point: Not requiring developers to install complicated dependencies such as protoc manually.

• [ ] Fully automated dependency installation
• [ ] Version-control .proto files(messages/), but add generated Rust(native/hub/src/messages/)/Dart(lib/messages/) code to .gitignore.

Dart Side

• https://grpc.io/docs/languages/dart/quickstart/
• https://protobuf.dev/getting-started/darttutorial/

Rust Side

• https://github.com/hyperium/tonic/issues/56#issuecomment-539716638
• https://youtu.be/JkSa-qA2jnY

Both

• https://grpc.io/docs/protoc-installation/