feat: nodes should die entirely if no MCU found

This should allow anchor to restart automatically if it's being run as a service

src/anchor_pkg/anchor_pkg/anchor_node.py

@@ -7,6 +7,7 @@ import time
 import atexit
 
 import serial
+import os
 import sys
 import threading
 import glob
@@ -61,8 +62,9 @@ class SerialRelay(Node):
         
         if self.port is None:
             self.get_logger().info("Unable to find MCU...")
-            time.sleep(1)
-            sys.exit(1)
+            #kill the node/process entirely
+            os.kill(os.getpid(), signal.SIGKILL)
+            sys.exit(0)
         
         self.ser = serial.Serial(self.port, 115200)
         atexit.register(self.cleanup)