Goal: 

ArgoCD has support for hooks, hitting at various time over the application lifecycle. Some resources must be deleted outside of ArgoCD, because it doesn't know at all about them.

For instance:

• all OpenStackDataPlaneService must be deleted once DataPlaneDeployment and DataPlaneNodeset are deleted
• all PVCs must be deleted once ControlPlane is deleted (mostly database related volumes)
• ...

Acceptance Criteria:

• A list of potential hooks is provided
• Associated tasks are created, to propose needed hooks