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/s6-overlay/s6-rc.d/prepare/50-ipv6.sh

@@ -5,8 +5,6 @@
 # or disable ipv6 in all nginx configs based on this setting.
 
 set -e
-# verbose
-set -x
 
 log_info 'IPv6 ...'
 
@@ -33,7 +31,7 @@ process_folder () {
 		sed -E -i "$SED_REGEX" "$FILE"
 	done
 
-	# ensure the files are still owned by the npmuser
+	# ensure the files are still owned by the npm user
 	chown -R "$PUID:$PGID" "$1"
 }