abuild: Do not enable nftables ruleset automatically
As discussed in the aports merge request, we think it is better to not enable the ruleset by default. Mainly because then an installed package would make holes in the firewall, even if the users does not run the software.
If we install the ruleset in a different folder, the users can symlink what they needs. They can symlink all hooks, or the directory, or use them however they wants.
This store the nft ruleset in /usr/share/nftables.avail/ as discussed upstream: