__pf_apply the way it exists on cdist is not really useful and __pf_ruleset does
not take advantage of other types as it should, being instead overly complex and
not as reliable.
The new __pf_ruleset is compatible with the previous one, and __pf_apply_anchors
allows for a simple and powerful way of managing pf anchors.
The functionality previously provided by __pf_apply is still possible out of the
box in __pf_ruleset.
These patches were mostly contributed by Kamila Součková and made fit for
upstreaming by Evilham.