Provide option for using non-deprecated amazon instances with fck-nat

[mwillbanks]

fck-nat provides the same behavior as the amazon nat instances, with the exception that it is up to date and can be run on the arm64 platforms thus reducing overall cost. since several people already have the existing deployed, it makes more sense to provide an option to allow them to use it.

When using createNatInstance = true AND createNatInstanceFckNat = true, this will then utilize the FckNat instances rather than the deprecated amazon instances.

[jplock]

What do you think about making this the default to replace the amazon-managed AMI?

[mwillbanks]

@jplock i think it's the right idea, my only concern was those that already have one running and swapping instance types could create some temporary downtime for them, therefore I thought it would be best not to touch it and instead add an additional option....

I actually had started thinking about extending the option support as well to make the entirety of the nat interface configurable since you can actually run the fck-nat on different instance types as well (but thats for another time).

[jplock]

I'm going to close this PR. Thank you for the contribution. I'm going to archive this repo as I no longer use this plugin.