run pkm runtime as dedicated user instead of root
In the same manner @chalendar mitigated this in ner_tool#2 (closed), we need to deal with the PKM container.
UID PID PPID C STIME TTY TIME CMD
-------------------------------------------------------------------------------------------------
root 26098 26041 0 Jan06 ? 00:00:00 /bin/bash ./docker/start.sh
root 26405 26098 0 Jan06 ? 00:00:00 bash ./start_server.sh
root 26409 26405 0 Jan06 ? 00:00:00 npm
root 26546 26409 0 Jan06 ? 00:00:00 sh -c node --max-old-space-size=8192 index.js
root 26547 26546 0 Jan06 ? 00:00:02 node --max-old-space-size=8192 index.js