feature: only_if for profiles added

Signed-off-by: Dominik Richter <dominik@vulcanosec.com>

lib/vulcano/rule.rb

@@ -27,6 +27,7 @@ end
 
 module Vulcano::DSL
   def rule id, opts = {}, &block
+    return if @skip_profile
     __register_rule Vulcano::Rule.new(id, opts, &block)
   end
 
@@ -34,6 +35,11 @@ module Vulcano::DSL
     __unregister_rule id
   end
 
+  def only_if &block
+    return unless block_given?
+    @skip_profile = !block.()
+  end
+
   def require_rules id, &block
     ::Vulcano::DSL.load_spec_files_for_profile self, id, false, &block
   end