feat: basic PDS playbook

vars/main.yml.example

@@ -0,0 +1,8 @@
+# Required
+pds_hostname: pds.example.com
+pds_admin_email: admin@example.com
+
+# Optional (defaults shown)
+# pds_data_dir must be /pds — the installer enforces this
+pds_data_dir: /pds
+pds_image_tag: "0.4"