Feature: Add Multer Middleware to Upload Tour Pictures

Currently, the Tour model accepts a photo as a string URL. To make the backend more flexible and user-friendly, we need to integrate multer middleware to handle image uploads.

This enhancement will allow users or admins to upload tour images directly through the API, and the backend will store the file (locally or in cloud storage, depending on future config). The uploaded file's path or URL will then be saved in the photo field of the tour.

@adityakalburgi plzz assign this issue to me i would like to work on it