cleanup: follow-up tasks for monorepo structure

[embik]

We have migrated successfully to a monorepo structure, but #3638 was just a bandaid for a couple of things. We have to finalize the migration by doing the following things:

• Stop ignoring staging repositories for the boilerplate check and instead run boilerplate checks on all of them.
• Test and validate module version replacements done by publishing-bot to ensure that modules depend on the right versions of each other.
• Stop ignoring staging repositories for linting.
• Remove leftover artifacts from staging repositories (e.g. .prow.yaml files).
• Ensure that test pipelines cover staging repositories (to substitute adequately for the prow jobs that covered them previously).
• bug: sdk is not go install'able anymore #3653

If you find more, please consider adding it here.

[xmudrii]

In-depth testing has been done via v0.29.0-rc.0 and v0.29.0-rc.1 releases. Tags are getting properly pushed to the published repositories. go.mod files are getting correctly manipulated and updated. publishing-bot status is green and stable.

🎉 🟢

/close

[kcp-ci-bot]

@xmudrii: Closing this issue.

In response to this:

In-depth testing has been done via v0.29.0-rc.0 and v0.29.0-rc.1 releases. Tags are getting properly pushed to the published repositories. go.mod files are getting correctly manipulated and updated. publishing-bot status is green and stable.

🎉 🟢

/close

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