Webhook enablement should be a CLI flag

[diranged]

Is this a BUG REPORT or FEATURE REQUEST?:

Changing webhook.enabled from false to true seems like it needs to be a CLI argument that triggers a new deployment of the app.

What happened:

When you just switch the configmap from webhook.enabled: 'false' to webhook.enabled: 'true', the iam-manager reloads the configmap but it does not start listening on port 9443. However, it DOES create the registration with the API. This causes new requests for those resources to start failing. It seems like this should just be a CLI argument rather than a configmap setting because it fundamentally alters the way the code behaves and requires the code to begin listening on a new port.