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-2094/adding-dependencies-and-grpc-tonic-core-in-tunnelbroker-rust | ENG-2094 ]]