Use tpl on network policies custom rules to allow for dynamic values

[xr09]

For large scenarios, sometimes we need to reference a namespace or a label containing some dynamic value.

With this change, we'll be able to use any variable in the custom rules.

customRules:
  - to:
    - namespaceSelector:
      matchLabels:
        kubernetes.io/metadata.name: data-stream-{{ .Values.dynamic.value }}

[xr09]

Done. Thanks @azatsafin!