cleanup of controller owned firewalls

[hcwagner]

Running helm uninstall or rollback will delete the controller and associated manifests from the cluster, but will leave existing firewalls deployed in the cloud infra (Cloud Manager/Linode API).

When deleting the installation of the controller it should check for all CloudFirewalls that are not imported (i.e. owned by something else) and delete them prior to removing the controller.

This will require:

• finalizer for the controller
• ownership information to be persisted in the CloudFirewall object state

[hcwagner]

Currently any CloudFirewall CR that is instantiated inside a cluster with the controller installed will be cleaned up when the controller is uninstalled via helm.

Example uninstall command: KUBECONFIG=./my-config.yaml helm delete cloud-firewall-release

This will result in all CRs being cleaned up do to ownership references.

Deleting the cluster via the Linode API or UI will result in dangling Cloud Firewalls existing in the users Linode account. This is due to the deletion of the cluster not issuing a graceful deletion of resources inside the LKE. Future updates may be able to alleviate this issue.