Changelog:
- update man page for limit since IPv6 has been supported since 0.33
- add direction when no interfaces specified in get_app_tuple()
- various testsuite adjustments for iptables 1.8
- empty out IPT_MODULES and update documentation
- adjust check-requirements to look for other firewall software
- src/backend_iptables.py: unconditionally reload user rules with 'delete'
Signed-off-by: Algent Albrahimi <algent@protonmail.com>