Now update-generated-proto-bindings rules all the api.pb.go generation.
Running this shows no delta on the runtime.pb.go
This exposes an issue in how protoc is called for protos that specify
`go_package` which is fixed here.
Not all of our protos specify that option (even though it is
recommended), which will be fixed subsequently.
Each of these scripts is basically identical, and all were too brittle.
Now they should be more resilient and easier to manage. The script
still needs to be updated if we add new ones, which I do not love.
More cleanup to follow.