Create protobuf item template

[JunTaoLuo]

[ryanbrandenburg]

I don't like that we're creating templates for protocols/techs that we don't own, especially considering that it can be as simple as syntax = "proto3";.

[analogrelay]

We have a whole gRPC template. It seems entirely reasonable to have a protobuf file template to me given that we are promoting this as a primary scenario.