add prometheus

don't publish traefik api

roles/prometheus/templates/docker-compose.yml.j2

@@ -0,0 +1,13 @@
+version: "3.8"
+
+services:
+  prometheus:
+    image: prom/prometheus
+    container_name: prometheus
+    restart: always
+    volumes:
+      - "{{ service_dir }}/prometheus.yml:/etc/prometheus/prometheus.yml"
+    extra_hosts:
+      - "host.docker.internal:host-gateway"
+    ports:
+      - "{{ prometheus_port }}:9090"

roles/prometheus/templates/prometheus.yml.j2

@@ -0,0 +1,14 @@
+global:
+  scrape_interval:     15s
+
+scrape_configs:
+
+  - job_name: 'prometheus'
+    scrape_interval: 5s
+    static_configs:
+      - targets: ['localhost:9090']
+
+  - job_name: 'traefik'
+    scrape_interval: 5s
+    static_configs:
+      - targets: ['host.docker.internal:{{ traefik_api_port }}']