Initialise repository structure and placeholder files. Generic functionality works i guess, need to come up with a better solution for compose templates

roles/prometheus/defaults/main.yml

@@ -0,0 +1,19 @@
+---
+prometheus_name: prometheus
+prometheus_dir: /srv/docker/prometheus
+prometheus_image: prom/prometheus:latest
+prometheus_domain: prometheus.example.invalid
+prometheus_service_port: 9090
+prometheus_routing_mode: host
+prometheus_command: "--config.file=/etc/prometheus/prometheus.yml --storage.tsdb.path=/prometheus"
+prometheus_env: {}
+prometheus_directories:
+  - "{{ prometheus_dir }}"
+  - /srv/config/prometheus
+  - /srv/data/prometheus
+prometheus_volumes:
+  - /srv/config/prometheus:/etc/prometheus
+  - /srv/data/prometheus:/prometheus
+prometheus_ports:
+  - { host: 9090, container: 9090, protocol: tcp }
+