[PR #2951/c7c7f15b backport][stable-9] Implement integration tests

[patchback]

This is a backport of PR #2951 as merged into main (c7c7f15).

SUMMARY

This PR migrates our integration testing suite from legacy Zuul infrastructure to GitHub Actions. It introduces a robust workflow triggered on pull_request events to ensure code quality and functional correctness before merging.

Key Changes:

Modernized CI: Established a GHA workflow that leverages the pull_request trigger and path filtering to optimize runner usage.

Secure Credential Provisioning: Integrated ansible/ansible-test-auth@v1 to dynamically generate short-lived cloud credentials. This replaces the need for static secrets and aligns with our OIDC security goals.

ISSUE TYPE

• Feature Pull Request

[centosinfra-prod-github-app]

Build succeeded.
https://gateway-cloud-softwarefactory.apps.ocp.cloud.ci.centos.org/zuul/t/ansible/buildset/81521e2b1366440b972a914ada3b6369

✔️ ansible-galaxy-importer SUCCESS in 3m 52s
✔️ build-ansible-collection SUCCESS in 9m 21s
✔️ ansible-test-splitter SUCCESS in 3m 05s
✔️ integration-amazon.aws-1 SUCCESS in 6m 34s
✔️ integration-amazon.aws-2 SUCCESS in 3m 24s
Skipped 42 jobs

[centosinfra-prod-github-app]

Build succeeded.
https://gateway-cloud-softwarefactory.apps.ocp.cloud.ci.centos.org/zuul/t/ansible/buildset/1f06ed77a23e47608c98e39eda400114

✔️ ansible-galaxy-importer SUCCESS in 5m 50s
✔️ build-ansible-collection SUCCESS in 11m 26s
✔️ ansible-test-splitter SUCCESS in 4m 32s
✔️ integration-amazon.aws-1 SUCCESS in 6m 10s
✔️ integration-amazon.aws-2 SUCCESS in 3m 35s
Skipped 42 jobs