Add support for bzlmod

[Vertexwahn]

Add support for bzlmod:

• Add Bazel module support
• Add rules_ruby to Central Bazel Registry

[alexeagle]

I have bumped into this need as well due to the dependency from protobuf -> rules_ruby, and we need the former on the central registry.
However, for some reason the protocolbuffers org has forked the rules: protocolbuffers/protobuf#14569
@kigster do you have any history of why they did that? It will be terrible for users if multiple forks of rules_ruby end up on BCR so I think we need some effort to converge them again.

[alexeagle]

https://github.com/p0deje/rules_ruby is another fork from @shs96c Selenium team

[alexeagle]

Filed bazelbuild/bazel-central-registry#1083