MINOR: http/hardening: turn it to a macro and count matches with COUNT_IF()

MINOR: http/hardening: turn it to a macro and count matches with COUNT_IF()

Thanks to COUNT_IF() it is quite easy to count the number of times the
condition for a given hardening flag was met, and the number of times it
was enforced. Let's replace the function by a macro for this. In order
to avoid counting multiple times the same match (e.g. many CTL chars in
a header value), the macro takes care of checking both the found and the
rules flags. This way we have at least one found per enforcement, and at
least one per distinct match but not necessarily more if no enforcement
is configured.