Check in proto generated go files

[csmarchbanks]

Right now we do not check in any of the *.pb.go files that are generated.

During the May 2nd Community Meeting we generally decided a good direction to go would be to:

1. Check in all generated code.
2. Pin to a specific gogo/protobuf version see We don't know which gogoproto we are using #1370.
3. Create a CI job that fails if the checked in version does not match a newly generated version.