feat: support jetty agent shell (#19)

1. hook point is org.eclipse.jetty.servlet.ServletHandler.doHandle
2. it doesn't support jetty6, org.mortbay.jetty.servlet.ServletHandler#handle, because ldc visit cannot support java1.4

integration-test/script/jetty_pid.sh

@@ -0,0 +1,2 @@
+#!/bin/bash
+ps -ef | grep "jetty.home" | grep -v grep | awk '{print $2}' | tr -d '\n'