Review all iptables commands for the openSUSE Leap 16.0 release currently live on GCP

[glovecchi0]

In the Google Cloud environment, where the openSUSE Leap 16.0 image was released, the following no longer work:

• the harvester-ops/network-creation project
• the air-gapped option

The problem is that iptables is no longer used in the new OS.

PS: If you are using the 15.6 certified image there is NO problem.
https://github.com/rancher/harvester-cloud/releases/tag/build-5

[glovecchi0]

The goal here is to migrate from iptables to nftables, so that the configurations are valid for both openSUSE Leap 1.15 and the new 1.16.

The steps to follow are:

1. Migrate the configurations
2. Test the deployment in all 3 cloud providers (airgapped mode + harvester-ops/network-creation) with the image available in the cloud
3. Perform the same tests with the certified image 1.15.6 released in the repository

GCP already has version 1.16, so compatibility can be tested with that provider.