add postgres exporter

Signed-off-by: Tuan-Dat Tran <tuan-dat.tran@tudattr.dev>

roles/postgres_exporter/tasks/systemd.yml

@@ -0,0 +1,10 @@
+---
+- name: "Ensure service is running and enabled: {{ bin_name }}"
+  ansible.builtin.service:
+    name: "{{ bin_name }}"
+    state: started
+    daemon_reload: true
+    enabled: true
+  notify:
+    - Restart "{{ bin_name }}"
+  become: true