Add a minimal debugging tool to show the UI while device not in car (#1937)

* add a minimal uiview file with alias from selfdrive/ui

* make ui_debug executable

* minimize uiview.py; remove os and functions. the processes exit normally when ctrl+c'ing out of the loop

* violating E401 here, save 1 more line

* kill on exit

* forgot signal

* new record! 15 lines

* add comments and declare some common variables. don't need to redefine the messages every loop
old-commit-hash: 2e59349b2e

selfdrive/debug/uiview.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+import time
+import cereal.messaging as messaging
+from selfdrive.manager import start_managed_process, kill_managed_process
+
+services = ['controlsState', 'thermal']  # the services needed to be spoofed to start ui offroad
+procs = ['camerad', 'ui']
+[start_managed_process(p) for p in procs]  # start needed processes
+pm = messaging.PubMaster(services)
+
+dat_cs, dat_thermal = [messaging.new_message(s) for s in services]
+dat_cs.controlsState.rearViewCam = False  # ui checks for these two messages
+dat_thermal.thermal.started = True
+
+try:
+  while True:
+    pm.send('controlsState', dat_cs)
+    pm.send('thermal', dat_thermal)
+    time.sleep(1 / 100)  # continually send, rate doesn't matter for thermal
+except KeyboardInterrupt:
+  [kill_managed_process(p) for p in procs]