Goal:
ONAP OOM team is planning an update of the K8S platform used by ONAP from K8S 1.15 -> 1.17. As a consequence, the DCAE CFY K8S Plugin needs to be updated too.

Proposal:
The K8S APIs beta/v1apps has been migrated to apps/v1 in K8S 1.16.
If they exist in K8S 1.15, then the plugin shall start using these APIs, while we keep ONAP on K8S 1.15. When ONAP will update it`s K8S environment to K8S 1.17, we shall need no new plugin changes.

It is expected, that the DCAE CFY K8S Plugin update is needed due to Kubernetes 1.15 EOL (happended already in March 2020).