Evaluate using buf's protoc to get rid of C deps

[leoluk]

Much of the work done by Bazel during a clean NetMeta build is related to building protoc.

Perhaps we can use buf's pure-Go protoc instead? Probably a performance win, too.

[leoluk]

rules_proto comes with a prebuilt protoc toolchain: https://github.com/bazelbuild/rules_proto

We should be able to use that to avoid that step.

[fionera]

I just tried buf for a different project and its fairly simple. I would prefer it over the prebuilt chain

[leoluk]

With Bazel?

[leoluk]

Tricky part is convincing rules_proto use the buf protoc