Add php8.1 service files

etc/systemd/system/php8.1-fpm.service

@@ -0,0 +1,16 @@
+# This service is actually a systemd target,
+# but we are using a service since targets cannot be reloaded.
+
+[Unit]
+Description=The PHP 8.1 FastCGI Process Manager (multi instance master)
+Documentation=man:php-fpm8.1(8)
+After=network.target
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/bin/true
+ExecReload=/bin/true
+
+[Install]
+WantedBy=multi-user.target