unifi: Deploy unifi_exporter

`unifi_exporter` provides Prometheus metrics for UniFi controller.

roles/unifi/tasks/exporter.yml

@@ -0,0 +1,58 @@
+- name: ensure unifi_exporter is configured
+  copy:
+    dest: /etc/unifi_exporter.yml
+    content: >-
+      {{ unifi_exporter_config | to_nice_yaml(indent=2) }}
+    mode: u=rw,g=r,o=
+    owner: root
+    group: 200
+  notify:
+  - restart unifi_exporter
+  tags:
+  - config
+
+- name: ensure unifi_exporter container is configured
+  template:
+    src: unifi_exporter.container.j2
+    dest: /etc/containers/systemd/unifi_exporter.container
+    mode: u=rw,go=r
+    owner: root
+    group: root
+  notify:
+  - reload systemd
+  - restart unifi_exporter
+  tags:
+  - container
+
+- name: ensure unifi_exporter container image is present
+  podman_image:
+    name: '{{ unifi_exporter_container_image }}:{{ unifi_exporter_version }}'
+    state: present
+  tags:
+  - container
+
+- name: flush handlers
+  meta: flush_handlers
+
+- name: ensure unifi_exporter service is enabled
+  systemd:
+    name: unifi_exporter
+    enabled: true
+  tags:
+  - service
+- name: ensure unifi_exporter service is running
+  systemd:
+    name: unifi_exporter
+    state: started
+  tags:
+  - service
+
+- name: ensure firewall is configured for unifi_exporter
+  firewalld:
+    port: 9130/tcp
+    state: enabled
+    permanent: true
+    immediate: true
+  when: host_uses_firewalld|d(true)
+  tags:
+  - firewalld