feat: refactor quest models

+ separate stage and exception
+ reuse commandResponder

packages/models/commandResponder.js

@@ -0,0 +1,19 @@
+import { Schema } from 'mongoose'
+import conditionSchema from './condition.js'
+import responseSchema from './response.js'
+import hintSchema from './hint.js'
+
+const commandResponderSchema = new Schema({
+  condition: {
+    type: conditionSchema,
+    required: false,
+  },
+  responses: {
+    type: [responseSchema],
+    required: true,
+  },
+})
+
+commandResponderSchema.add(hintSchema)
+
+export default commandResponderSchema