enhancement(prometheus): support prometheus2 .yml rule file format

roles/prometheus/meta/argument_specs.yml

@@ -130,14 +130,14 @@ argument_specs:
       prometheus_alert_rules:
         description:
           - "Full list of alerting rules which will be copied to C({{ prometheus_config_dir }}/rules/ansible_managed.rules)."
-          - "Alerting rules can be also provided by other files located in C({{ prometheus_config_dir }}/rules/) which have C(*.rules) extension"
+          - "Alerting rules can be also provided by other files located in C({{ prometheus_config_dir }}/rules/) which have a C(*.rules) or C(*.rules.yml) extension"
           - "Please see default values in role defaults/main.yml"
         type: "list"
         elements: "dict"
       prometheus_alert_rules_files:
         description:
           - "List of folders where ansible will look for files containing alerting rules which will be copied to C({{ prometheus_config_dir }}/rules/)."
-          - "Files must have C(*.rules) extension"
+          - "Files must have a C(*.rules) or C(*.rules.yml) extension"
         type: "list"
         elements: "str"
         default:

roles/prometheus/templates/prometheus.yml.j2

@@ -20,6 +20,7 @@ remote_read:
 {% if not prometheus_agent_mode and prometheus_alert_rules_files != [] %}
 rule_files:
   - {{ prometheus_config_dir }}/rules/*.rules
+  - {{ prometheus_config_dir }}/rules/*.rules.yml
 {% endif %}
 
 {% if prometheus_alertmanager_config | length > 0 %}