Auditbeat: align Buildkite steps to match Jenkins

[oakrizan]

Proposed commit message

1. Updated auditbeat pipeline to match same steps & commands as in Jenkins on 7.17 branch
2. Removed dynamic pipeline generation script generate_auditbeat_pipeline.sh - leftover, not required anymore, deleted from main as well.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Disruptive User Impact

Author's Checklist

• .buildkite/auditbeat/auditbeat-pipeline.yml

How to test this PR locally

Related issues

• Relates https://github.com/elastic/ingest-dev/issues/3254

Use cases

Screenshots

Logs

Buildkite builds: https://buildkite.com/elastic/auditbeat/builds?branch=oakrizan%3Aaligning-auditbeat-with-7-17

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b aligning-auditbeat-with-7-17 upstream/aligning-auditbeat-with-7-17
git merge upstream/7.17
git push upstream aligning-auditbeat-with-7-17

[dliappis]

LGTM