feat: implement QuestionBank CRUD with pagination and template query

- Add pagination support to findAll (page, limit query params)
- Add findByTemplateId method to service
- Add GET /by-template/:templateId endpoint to controller
- Service already includes CRUD for QuestionBank and QuestionBankItem

web/postcss.config.js.bak

@@ -0,0 +1,6 @@
+export default {
+    plugins: {
+        tailwindcss: {},
+        autoprefixer: {},
+    },
+}