[ci] Stop using personal domain for CI (#1322)

Migrate away from using a private domain for build infra.

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## What this PR does


### Release note

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```release-note
[]
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## Summary by CodeRabbit

* **Chores**
* Updated container image registry mirror URLs in the cluster
configuration to use a new domain.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

hack/e2e-prepare-cluster.bats

@@ -136,25 +136,25 @@ machine:
     mirrors:
       docker.io:
         endpoints:
-        - https://dockerio.nexus.lllamnyp.su
+        - https://dockerio.nexus.aenix.org
       cr.fluentbit.io:
         endpoints:
-        - https://fluentbit.nexus.lllamnyp.su
+        - https://fluentbit.nexus.aenix.org
       docker-registry3.mariadb.com:
         endpoints:
-        - https://mariadb.nexus.lllamnyp.su
+        - https://mariadb.nexus.aenix.org
       gcr.io:
         endpoints:
-        - https://gcr.nexus.lllamnyp.su
+        - https://gcr.nexus.aenix.org
       ghcr.io:
         endpoints:
-        - https://ghcr.nexus.lllamnyp.su
+        - https://ghcr.nexus.aenix.org
       quay.io:
         endpoints:
-        - https://quay.nexus.lllamnyp.su
+        - https://quay.nexus.aenix.org
       registry.k8s.io:
         endpoints:
-        - https://k8s.nexus.lllamnyp.su
+        - https://k8s.nexus.aenix.org
   files:
   - content: |
       [plugins]