add firewalld FORWARD rule

[dellnoantechnp]

add firewalld FORWARD rule in PostUp & PostDown stage.

Rule Example:
PostUp:

• firewall-cmd --direct --add-rule ipv4 filter FORWARD 1 -i ${SERVER_WG_NIC} -j ACCEPT
• firewall-cmd --direct --add-rule ipv4 filter FORWARD 1 -o ${SERVER_WG_NIC} -j ACCEPT

PostDown:

• firewall-cmd --direct --remove-rule ipv4 filter FORWARD 1 -i ${SERVER_WG_NIC} -j ACCEPT
• firewall-cmd --direct --remove-rule ipv4 filter FORWARD 1 -o ${SERVER_WG_NIC} -j ACCEPT