Added ACCEPT to TEMPLATE using FW_SERVICES_ACCEPT

Allows to open ports for IPv6 only or IPv4 only using
::/0 or 0.0.0.0/0 as net (source address net) in same
way as the RELATED variable.
Merge pull request #3 from mtomaschewski/accept-template

Added ACCEPT to TEMPLATE using FW_SERVICES_ACCEPT