`node_groups()` to puppet code

[WhatsARanjit]

The node_groups() functions presents raw data, but it is not very usable because of all the "extra" data provided in it. Need to provide a cleaner version that:

• Omits ensure attribute (if there)
• Omits id because it is a read-only attribute

And maybe more...

[WhatsARanjit]

The idea here is to provide a flag that omits the data that isn't directly reusable into puppet code.