fix(userspace/engine): cache latest rules compilation output

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

userspace/engine/falco_engine.h

@@ -40,6 +40,7 @@ limitations under the License.
 #include "falco_load_result.h"
 #include "filter_details_resolver.h"
 #include "rule_loader_reader.h"
+#include "rule_loader_compiler.h"
 
 //
 // This class acts as the primary interface between a program and the
@@ -347,6 +348,8 @@ private:
 	std::map<std::string, uint16_t> m_known_rulesets;
 	falco_common::priority_type m_min_priority;
 
+	std::unique_ptr<rule_loader::compiler::compile_output> m_last_compile_output;
+
 	//
 	// Here's how the sampling ratio and multiplier influence
 	// whether or not an event is dropped in