Use nftables instead of iptables where it is supported.

[wintermu7e]

Use Case

When doing CIS compliance, using iptables on rhel8 and rhel9 is problematic, as on both of these OS's iptables actually uses components of nftables in the backend. As nftables is the preferred method on these OS it makes sense to use it rather than iptables. In fact on rhel9 iptables is not even one of the alternatives in the CIS lockdown document.

Describe the Solution You Would Like

I would like to see the module use nftables rather than iptables when the OS is has nftables. nftables is the preferred method for rhel8 and up. See the rhel8 release notes https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/8.0_release_notes/index#networking

Describe Alternatives You've Considered

Can continue to use IPtables and just live with CIS audit failures, as the firewall is working, it just doesn't match the CIS compliance model.

Additional Context

At some point redhat is likely to drop support for iptables all together. It would make sense to be ahead of the curve and already be using the new method where available.