src: Simplify parser rule_spec tree

src: Simplify parser rule_spec tree

This patch separates the rule identification from the rule localization,
so the logic moves from the evaluator to the parser. This allows to
revert the patch "evaluate: improve rule managment checks"
(4176c7d30c2ff1b3f52468fc9c08b8df83f979a8) and saves a lot of code.

Signed-off-by: Carlos Falgueras García <carlosfg@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>