refactor: consolidate all roles into ansible/roles/ and update ansible.cfg

- Move all roles from playbooks/roles/ to roles/
- Update roles_path in ansible.cfg
- Add cast user to common role
- Create standalone podman role
- Add semaphore role with Podman + Quadlet support

ansible/roles/observer/templates/alertmanager/alertmanager.j2

@@ -0,0 +1,13 @@
+route:
+  receiver: "mail"
+  repeat_interval: 4h
+  group_by: [ alertname ]
+
+receivers:
+  - name: "mail"
+    email_configs:
+      - smarthost: "outlook.office365.com:587"
+        auth_username: "test@padok.fr"
+        auth_password: "{{ alertmanager_smtp_password }}"
+        from: "test@padok.fr"
+        to: "test@padok.fr"