* first adjustments to use Fail2Ban with nftables
* replace `iptables` -> `nftables` and adjust tests
nftables lists IPs a bit differently , so the order was adjusted for the
tests to be more flexible.
* line correction in mailserver.env
* change from `.conf` -> `.local` and remove redundant config
* revert HEREDOC to `echo`
Co-authored-by: Casper <casperklein@users.noreply.github.com>
