CC-4974: Watchdog for ensuring Liquidsoap does not consume more than 1GB of memory

-changed to 600MB for now. May lower even more later

python_apps/pypo/monit-airtime-liquidsoap.cfg

@@ -1,4 +1,4 @@
- set daemon 10 # Poll at 5 second intervals
+ set daemon 15 # Poll at 5 second intervals
  set logfile /var/log/monit.log
 
  set httpd port 2812
@@ -7,3 +7,10 @@
     with pidfile "/var/run/airtime-liquidsoap.pid"
     start program = "/etc/init.d/airtime-liquidsoap start" with timeout 5 seconds
     stop program = "/etc/init.d/airtime-liquidsoap stop"
+
+    if mem > 600 MB for 3 cycles then restart
+    if failed host localhost port 1234
+      send "version\r\nexit\r\n"
+      expect "Liquidsoap"
+      retry 3
+    then restart