This diff introduces adding the protobuf file compilation to Cargo's build system.
This is an intentional requirement to use [[ https://github.com/hyperium/tonic | Tonic ]].
Related Linear task: [[ https://linear.app/comm/issue/ENG-1072/use-rust-tonic-crate-in-tunnelbroker-to-implement-messagesstream | ENG-1072 ]]