feat: Added ownerRef to agent created webhook config.

[Ealianis]

Description of your changes

Updated the validating webhook configuration to have an owner reference to the fleet-system namespace.

Fixes #345

I have:

• Run make reviewable to ensure this PR is ready for review.

How has this code been tested

TBA

[Ealianis]

@Arvindthiru , as discussed there are multiple solutions to the problem noted in issue #345. For the draft I went with the least impactful as the owner reference approach seems the most intuitive. However, binding to the namespace feels odd. Ideally we would bind to the webhook service itself. Unfortunately due to the limitations of owner references we cannot, as the ValidatingWebhookConfig is a cluster scoped resource.

The other option could be a cleanup binary. But that may be overkill.

Thoughts?

[Arvindthiru]

@Arvindthiru , as discussed there are multiple solutions to the problem noted in issue #345. For the draft I went with the least impactful as the owner reference approach seems the most intuitive. However, binding to the namespace feels odd. Ideally we would bind to the webhook service itself. Unfortunately due to the limitations of owner references we cannot, as the ValidatingWebhookConfig is a cluster scoped resource.

The other option could be a cleanup binary. But that may be overkill.

Thoughts?

Binding the fleet-system namespace as the owner for ValidatingWebhookConfig seems slightly odd since the namespace wasn't the resource that was responsible for creating it. On the other hand it's a sure fire way to clean up any vestigial resources as we know for a fact that fleet-system will definitely get deleted when helm chart is uninstalled.

I guess it comes down to convention on whether this approach is valid

[Ealianis]

Verification

1. Execute Helm install of hub-agent.
2. Verify fleet-validating-webhook-configuration exists with OwnerRef pointing to fleet-system.
3. Verify pod creation is blocked.
4. Execute Helm uninstall of hub-agent.
5. Verify fleet-validating-webhook-configuration does not exist.
6. Verify pod creation is unblocked.