make stratos-clean on gke does not clean up the dns entries created upon deployment

[greygoo]

After you run make stratos-clean, the dns entries created upon deployment remain configured. This causes problems on deployments afterwards if a test or user tries to access stratos ui via the hostname as until the change has propagated, the wrong ip gets connected. This in some cases took over 10 minutes. A proper approach would be to remove the ip addresses from the dns setup once stratos gets deleted.