Rename webhook and open api urls (#11684)

We want to have fewer base path for routing.

We will have:
- /files
- /webhooks
- /graphql
- /metadata
- /rest
- /auth
- /healthz

I'm moving /open-api under /rest, and centralizing the webhooks
(removing /stripe and /cloudflare)

packages/twenty-server/src/engine/api/rest/core/controllers/rest-api-core.controller.ts

@@ -28,7 +28,7 @@ export class RestApiCoreController {
     private readonly restApiCoreServiceV2: RestApiCoreServiceV2,
   ) {}
 
-  @Post('/duplicates')
+  @Post('duplicates')
   @UseFilters(RestApiExceptionFilter)
   async handleApiFindDuplicates(@Req() request: Request, @Res() res: Response) {
     const result = await this.restApiCoreService.findDuplicates(request);