add postgres exporter

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

roles/postgres_exporter/tasks/main.yml

@@ -0,0 +1,7 @@
+---
+- name: Get Version
+  ansible.builtin.include_tasks: get_version.yml
+- name: Install exporter
+  ansible.builtin.include_tasks: install.yml
+- name: Create service
+  ansible.builtin.include_tasks: systemd.yml