[Enhancement] Migrate rpm-validation signature check functions to distribution-validation workflow

[peterzhuamazon]

Hi,

We used to have a pure groovy check for rpm-validation, focused on these:

• RPM signature validation
• RPM installation/runtime validation.
  https://github.com/opensearch-project/opensearch-build/blob/main/jenkins/rpm-validation/rpm-validation.jenkinsfile

The second part is already part of the distribution-validation, we want to migrate the 1st part to python code as well.

Thanks.

[prudhvigodithi]

[Triage]
Moving forward the the https://github.com/opensearch-project/opensearch-build/tree/main/src/validation_workflow workflow should be source of truth for all the validations.

[Divyaasm]

Rpm metadata and signature validation migrated to python workflow. Pending clean up of the existing rpm-validation jenkins job.

[Divyaasm]

Removed rpm-validation job status from dashboards