Transfer bazel-watcher to bazel-contrib

[meteorcloudy]

Description:

This issue proposes transferring the bazel-watcher repository from the bazelbuild GitHub organization to the bazel-contrib GitHub organization, which is owned by the Community for Bazel project under the Linux Foundation.

GitHub Discussion: https://github.com/orgs/bazelbuild/discussions/2

Impacts:

• GitHub issues & PRs will be transferred to the new repository.
• Branch protection rules will need to be transferred to the new repository.
• Individual maintainers will be transferred to the new repository.
• GitHub teams will NOT be transferred to the new repository and will need to be re-created.
• Bazel CI configurations will need to be updated to point to the new repository.

Read more on Transferring a repository from GitHub documentation.

Checklist:

• Obtain approval from the current project maintainers (@achew22 ).
• Obtain approval from the bazel-contrib SIG (@alexeagle).
• Initiate the transfer process on GitHub (@meteorcloudy).
• Update Bazel CI settings and confirm presubmit & postsubmit work (@meteorcloudy).

[alexeagle]

Notes from SIG meeting:

https://bazel-contrib.github.io/SIG-rules-authors/hosting-policy.html#adding-criteria
Criteria 9 is that this should work with bzlmod,
#647 seems like maybe it still requires a WORKSPACE file.

Consensus: let's not include this in today's bulk-transfer. Can be re-visited in a later SIG meeting.