[RFE] make control plane key configurable

[thoraxe]

Currently, via https://github.com/kubeflow/kfctl/pull/123 , a control-plane label is applied to namespaces where kubeflow is running. While this is well-intentioned (to prevent the application of kubeflow webhooks), it unfortunately causes collisions with other solutions.

This issue is a request for enhancement to make the key (control-plane) configurable.

An alternate suggestion would be to make the fixed key prefixed in some way. eg: kf-control-plane.

At this time, the control-plane label is causing an issue with knative serving deployments (no issue has been filed for that yet).

[slenky]

Upvoting it. In Azure that label also blocks Istio Injection for Kubeflow namespace because of https://github.com/Azure/AKS/issues/1771 Whenever I use kfctl to apply some changes I need to remove the control-plane label from Kubeflow namespace and rollout restart all the deployments.

[berndverst]

FYI @kubeflow/wg-manifests-leads