Add error to operator-builder CLI when cluster-scoped with no namespace resource

[lander2k2]

If a code base using cluster-scoped workload is created without a namespace child resource included, we should throw an error. This is because the resulting operator could attempt to create resources in a namespace that doesn't exist.

We should add a force flag so operator developer can override in the case they have good controls for namespace creation.

Error message something like:

You are using a cluster-scoped workload without a namespace child resource.  This could result in your controller attempting to create resources in a non-existent namespace.  Add the --force-cluster-scoped-without-ns flag to ignore this error message.