refactor(alertmanager): add state=absent support

roles/alertmanager/defaults/main/container.yml

@@ -0,0 +1,29 @@
+---
+alertmanager_container_name: alertmanager
+alertmanager_container_image_name: alertmanager
+alertmanager_container_image_namespace: prometheus/
+alertmanager_container_image_registry: quay.io
+
+alertmanager_container_image_repository: >-
+  {{
+    (container_registries[alertmanager_container_image_registry] | default(alertmanager_container_image_registry))
+    + '/' + (alertmanager_container_image_namespace | default(''))
+    + alertmanager_container_image_name
+  }}
+alertmanager_container_image_reference: >-
+  {{
+    alertmanager_container_image_repository + ':'
+    + (alertmanager_container_image_tag | default('v' + alertmanager_version))
+  }}
+alertmanager_container_image_source: pull
+alertmanager_container_image_force_pull: "{{ alertmanager_container_image_tag is defined }}"
+
+alertmanager_container_default_volumes:
+  - "{{ alertmanager_config_file }}:/etc/alertmanager/alertmanager.yml:ro"
+  - "{{ alertmanager_data_path }}:/alertmanager:rw"
+alertmanager_container_volumes: >-
+  {{ alertmanager_container_default_volumes
+     + alertmanager_container_extra_volumes | default([]) }}
+alertmanager_container_restart_policy: "unless-stopped"
+alertmanager_container_state: >-2
+  {{ (alertmanager_state == 'present') | ternary('started', 'absent') }}