add the ansible playbooks for the monitoring stack

ansible/roles/prometheus/templates/prometheus.service.j2

@@ -0,0 +1,30 @@
+[Unit]
+Description=Prometheus Monitoring System
+Documentation=https://prometheus.io/docs/
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+Type=simple
+User=monitoring
+Group=monitoring
+ExecReload=/bin/kill -HUP $MAINPID
+ExecStart=/usr/local/bin/prometheus \
+  --config.file=/etc/prometheus/prometheus.yml \
+  --storage.tsdb.path=/var/lib/prometheus \
+  --storage.tsdb.retention.time=15d \
+  --web.listen-address=0.0.0.0:9090 \
+  --web.enable-lifecycle \
+  --log.level=info
+
+SyslogIdentifier=prometheus
+Restart=always
+RestartSec=5
+
+# Hardening
+NoNewPrivileges=true
+ProtectSystem=full
+ProtectHome=true
+
+[Install]
+WantedBy=multi-user.target