allow dynamic namespace customization

[wasaga]

Is your feature request related to a problem? Please describe.

Currently, Ingress controller accepts namespaces to watch for Ingress resources via --namespaces runtime option, which may be manually provided via Deployment manifest or Helm chart parameter.

Describe the solution you'd like

As part of consolidating all Pomerium bootstrap configurations in a new Pomerium Settings CRD, add a Namespaces: []string parameter that may be dynamically reconfigurable.

Describe alternatives you've considered

Explain any additional use-cases

If there are any use-cases that would help us understand the use/need/value please share them as they can help us decide on acceptance and prioritization.

Additional context

Add any other context or screenshots about the feature request here.