Small refactor of user/groups and add checks during startup. Only use -x in bash scripts when DEBUG=true set in env vars

docker/rootfs/etc/nginx/nginx.conf

@@ -1,7 +1,7 @@
 # run nginx in foreground
 daemon off;
 pid /run/nginx/nginx.pid;
-user npmuser;
+user npm;
 
 # Set number of worker processes automatically based on number of CPU cores.
 worker_processes auto;