Refactor code structure for improved readability and maintainability.

Author: Emilianouz

.gitignore

@@ -1,2 +1 @@
 /node_modules
-package-lock.json

off-the-shelf-middleware/built-in-middleware.js

@@ -13,8 +13,6 @@ const usernameMiddleware = (req,res,next) => {
 
 // middleware for body parsing and validation
 
-app.use(express.text({ type: 'application/json'}));
-
 const validateArrayMiddleware = (req, res, next) => {
     // express.json() did the parsing, so..
     const data = req.body;