[JIRA] (OVIRT-1396) Add a new 'test-system-artifacts' Standard-CI stage

Add a new 'test-system-artifacts' Standard-CI stage --------------------------------------------------- Key: OVIRT-1396 URL: https://ovirt-jira.atlassian.net/browse/OVIRT-1396 Project: oVirt - virtualization made easy Issue Type: New Feature Components: oVirt CI Reporter: Barak Korren Assignee: infra This is a part of [containers CI/CD|https://docs.google.com/a/redhat.com/document/d/1mEo3E0kRvlUWT9VaSP...] flow implementation process. An order to allow building and testing processes for containers to be triggered after package that are needed for them are built, we will introduce the "{{test-system-artifacts}}" standard-CI stage. This stage will be invoked from the 'experimental' or 'change-queue-tester' pipelines jost like the existing OST-based flows. In order to provide package and repo information to the std-CI script invoked by this stage we well need to implement OVIRT-1391