Add N8n integration with models, services, and routes

- Introduced N8n and N8nSetting models in both MySQL and PostgreSQL schemas.
- Implemented N8nController and N8nService for managing N8n bots.
- Created N8nRouter for handling API requests related to N8n.
- Added DTOs and validation schemas for N8n integration.
- Updated server module and chatbot controller to include N8n functionality.
- Configured environment settings for N8n integration.

src/api/integrations/chatbot/chatbot.router.ts

@@ -6,6 +6,7 @@ import { Router } from 'express';
 
 import { EvolutionBotRouter } from './evolutionBot/routes/evolutionBot.router';
 import { FlowiseRouter } from './flowise/routes/flowise.router';
+import { N8nRouter } from './n8n/routes/n8n.router';
 
 export class ChatbotRouter {
   public readonly router: Router;
@@ -19,5 +20,6 @@ export class ChatbotRouter {
     this.router.use('/openai', new OpenaiRouter(...guards).router);
     this.router.use('/dify', new DifyRouter(...guards).router);
     this.router.use('/flowise', new FlowiseRouter(...guards).router);
+    this.router.use('/n8n', new N8nRouter(...guards).router);
   }
 }