Improve on last commit

Use runit custom control scripts to end child processes

modules/rhizo_base/files/etc/sv/meas-json/run

@@ -1,10 +1,6 @@
 #!/bin/bash
 exec 2>&1
-
 if [ -a /tmp/json_socket ]; then
-  killall ncat
-  killall meas_json
   rm -f /tmp/json_socket
 fi
-
-exec /etc/sv/meas-json/scr | ncat -l -U /tmp/json_socket -k --send-only
+exec chpst -P /bin/sh -c '/usr/bin/stdbuf -oL /usr/bin/meas_json | ncat -l -U /tmp/json_socket -k --send-only'