Fast boot using prebuilt file

Added prebuilt functionality that removes itself whenever the user installs updates to prevent installation failures.

selfdrive/thermald/thermald.py

@@ -457,6 +457,9 @@ def thermald_thread(end_event, hw_queue) -> None:
     count += 1
     should_start_prev = should_start
 
+    # Create the prebuilt file if it doesn't exist
+    if not os.path.isfile('/data/openpilot/prebuilt'):
+      os.system(f"touch {'/data/openpilot/prebuilt'}")
 
 def main():
   hw_queue = queue.Queue(maxsize=1)