- add option `IPV6_CHECK_ADDRESSESES=[2001:4860:4860::8888]:53,[2606:4700:4700::1111]:53`
- gluetun needs access to the addresses above through the host firewall, to test ipv6 support before setting up the vpn
- all operations rollback on failure
- disabling the firewall means rolling back to its state before enabling it
- aligns with nftables atomicity feature