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/10-usergroup.sh

@@ -0,0 +1,40 @@
+#!/command/with-contenv bash
+# shellcheck shell=bash
+
+set -e
+
+log_info "Configuring $NPMUSER user ..."
+
+if id -u "$NPMUSER" 2>/dev/null; then
+	# user already exists
+	usermod -u "$PUID" "$NPMUSER"
+else
+	# Add user
+	useradd -o -u "$PUID" -U -d "$NPMHOME" -s /bin/false "$NPMUSER"
+fi
+
+log_info "Configuring $NPMGROUP group ..."
+if [ "$(get_group_id "$NPMGROUP")" = '' ]; then
+	# Add group. This will not set the id properly if it's already taken
+	groupadd -f -g "$PGID" "$NPMGROUP"
+else
+	groupmod -o -g "$PGID" "$NPMGROUP"
+fi
+
+# Set the group ID and check it
+groupmod -o -g "$PGID" "$NPMGROUP"
+if [ "$(get_group_id "$NPMGROUP")" != "$PGID" ]; then
+	echo "ERROR: Unable to set group id properly"
+	exit 1
+fi
+
+# Set the group against the user and check it
+usermod -G "$PGID" "$NPMGROUP"
+if [ "$(id -g "$NPMUSER")" != "$PGID" ] ; then
+	echo "ERROR: Unable to set group against the user properly"
+	exit 1
+fi
+
+# Home for user
+mkdir -p "$NPMHOME"
+chown -R "$PUID:$PGID" "$NPMHOME"