refactor(userspace/engine): adapt existing ruleset implementation to new filter_ruleset interface

Signed-off-by: Jason Dellaluce <jasondellaluce@gmail.com>

userspace/engine/falco_rule.h

@@ -22,6 +22,7 @@ limitations under the License.
 
 struct falco_rule
 {
+	size_t id;
 	std::string source;
 	std::string name;
 	std::string description;