Add configuration to retain prometheus data for 1 year

Start monitoring prometheus to keep check of the database growth rate
and retain data for a longer preriod in prometheus.

roles/prometheus/files/prometheus.conf

+PROMETHEUS_ARGS="--storage.tsdb.retention.time=365d"

roles/prometheus/tasks/main.yml

@@ -7,6 +7,10 @@
   template: src=prometheus.yml.j2 dest=/etc/prometheus/prometheus.yml owner=root group=root mode=644
   notify: reload prometheus
 
+- name: install prometheus cli configuration
+  copy: src=prometheus.conf dest=/etc/conf.d/prometheus owner=root group=root mode=600
+  notify: reload prometheus
+
 - name: install prometheus alert configuration
   copy: src=node.rules.yml dest=/etc/prometheus/node.rules.yml owner=root group=root mode=644
   notify: reload prometheus