Bazel yq rule

This is a Bazel wrapper around yq, including a hermetic toolchain to fetch it.

From the documentation at https://mikefarah.gitbook.io/yq:

yq is a a lightweight and portable command-line YAML processor. yq uses jq-like syntax but works with yaml files as well as json.

API documentation: https://registry.bazel.build/modules/yq.bzl