Cap database connection pool size at 3 to respect Aiven connections ceiling

src/lib/db/pg/db.pg.ts

@@ -4,6 +4,8 @@ import { Pool } from "pg";
 const pool = new Pool({
   connectionString: process.env.POSTGRES_URL,
   ssl: { rejectUnauthorized: false },
+  max: 3,
+  idleTimeoutMillis: 300000,
 });
 
 export const pgDb = drizzlePg({ client: pool });