fix: changed req.ip to use x-forwarded-for unless not available

[AntonioRodriguezRuiz]

This pull request includes updates to the openapi.yaml file and several JavaScript files to enhance the logging of IP addresses by using the x-forwarded-for header when available. This change ensures that the correct client IP address is logged, even when the application is behind a proxy.

Updates to IP address logging:

• src/controllers/userController.js: Modified multiple functions (createUser, getUser, editUser, deleteUser) to log the IP address using req.headers['x-forwarded-for'] || req.ip. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

• src/controllers/validationController.js: Updated the validate function to log the IP address using req.headers['x-forwarded-for'] || req.ip.

• src/middleware/authMiddleware.js: Modified the userExists and authorizeRequest functions to log the IP address using req.headers['x-forwarded-for'] || req.ip. [1] [2] [3] [4] [5]

• src/middleware/validationMiddleware.js: Updated the validateToken function to log the IP address using req.headers['x-forwarded-for'] || req.ip. [1] [2]

Miscellaneous update:

• openapi.yaml: Changed the server URL to include /auth in the base path.