ci: migrate CI docker images to GCP

[rail]

Previously, we used Docker Hub to host our CI docker images.

To improve service reliability, this PR moves the used docker images to GAR.

Part of: DEVINF-915
Epic: RE-539
Release note: None

[cockroach-teamcity]

This change is 

[jlinder]

I was so excited to see this change happen that I jumped the gun and reviewed it while still a draft. 🤪 NM that review.

[rail]

It's fine. The change is ready to go, after I verify we can push the docker images from CI. No code changes expected, only permissions.

[rail]

bors r=jlinder

[craig]

Build failed:

• Bazel Essential CI (Cockroach)

[rail]

bors retry

[craig]

This PR was included in a batch that timed out, it will be automatically retried

[rail]

bors retry

[craig]

Already running a review

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error creating merge commit from f67e1ea to blathers/backport-release-23.1-117663: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 23.1.x failed. See errors above.

---

error creating merge commit from f67e1ea to blathers/backport-release-23.2-117663: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 23.2.x failed. See errors above.

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_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}