Regex for ignored and included namespaces

[avishefi]

The current --namespaces-to-ignore flag includes a plain text list of namespaces to ignore.

Add a regex for:

1. Namespaces to ignore - to allow bulk exclusion of namespaces
2. Namespaces to include - to avoid excluding all patterns and instead use a whitelist

[joebowbeer]

@avishefi ICYMI, it is possible to list namespaces to include:

namespaceSelector: kubernetes.io/metadata.name in (foo, bar)

[avishefi]

What about regex?