Separate bzlmod module for the Remote Output Service proto?

[sluongng]

Since we already have a separate module for the worker API, it would be nice to get one for the ROS protos as well, for easier consumption

https://github.com/bazelbuild/bazel-central-registry/tree/main/modules/bazel_worker_api

https://github.com/bazelbuild/bazel/blob/master/src/main/protobuf/bazel_output_service.proto
https://github.com/bazelbuild/bazel/blob/master/src/main/protobuf/bazel_output_service_rev2.proto

It would help folks adopting these proto files a bit easier than having to get the entire Bazel source bundle (or vendoring the protofiles)