Migrate to Bzlmod for managing external dependencies

[meteorcloudy]

With future Bazel LTS versions, Bzlmod will become the default system for external dependencies management.

Please consider migrating all your external dependencies in WORKSPACE to MODULE.bazel

For more information, please check bazelbuild/bazel#18958

[agluszak]

I can take care of this, but please first tell me if you're not working on it in your google-internal version.
cc @mai93