feat: manage database/user/grants for patroni

- add defines for exporting/collecting psql objects for patroni
- add generic profile for managing patroni psql databases for an app

site/profiles/manifests/sql/postgres/user.pp

@@ -0,0 +1,9 @@
+define profiles::sql::postgres::user (
+  String $username,
+  String $password,
+) {
+  postgresql_psql { "create_user_${username}":
+    command => "CREATE USER \"${username}\" WITH ENCRYPTED PASSWORD '${password}'",
+    unless  => "SELECT 1 FROM pg_roles WHERE rolname = '${username}'",
+  }
+}