1. Proposed title of this feature request

OLM Gatekeeper Operator Configuration: Separate Mutating/Validating Webhook namespaceSelector Config

2. What is the nature and description of the request?

On the Red Hat OLM Gatekeeper custom resource (gatekeepers.operator.gatekeeper.sh) we would request the ability to configure-separately per validating/mutating webhook-the namespaceSelector setting. Currently in the Gatekeeper CR, namespaceSelector is configurable, but only under the 'webhook' section which sets the same values on both mutating and validating Gatekeeper webhook configurations. To have better control over the Gatekeeper webhook configurations, we would like to be able to define something like:

apiVersion: operator.gatekeeper.sh/v1alpha1
kind: Gatekeeper
metadata:
  name: gatekeeper
spec:
  validatingWebhook:
    enabled: true
    namespaceSelector:
      matchExpressions:
      - key: kubernetes.io/metadata.name
        operator: NotIn
        values:
        - namespace-x
  mutatingWebhook: 
    enabled: true
    namespaceSelector:
      matchExpressions:
      - key: kubernetes.io/metadata.name
        operator: In
        values:
        - namespace-y 

3. Why does the customer need this? (List the business requirements here)
Unable to precisely configure the Gatekeeper installation if we use the OLM Gatekeeper operator

4. List any affected packages or components.