Move middleware into lib folder

This moves the `middleware` folder into the `lib` folder and updates file references to them.

This is to enable easier updates to the kit in future, as the main folder to copy across will just be the `lib` one.

app.js

@@ -16,14 +16,14 @@ dotenv.config();
 
 // Local dependencies
 const packageInfo = require('./package.json');
-const authentication = require('./middleware/authentication');
-const automaticRouting = require('./middleware/auto-routing');
+const authentication = require('./lib/middleware/authentication');
+const automaticRouting = require('./lib/middleware/auto-routing');
 const config = require('./app/config');
 const locals = require('./app/locals');
 const routes = require('./app/routes');
 const utils = require('./lib/utils');
 
-const prototypeAdminRoutes = require('./middleware/prototype-admin-routes');
+const prototypeAdminRoutes = require('./lib/middleware/prototype-admin-routes');
 const exampleTemplatesRoutes = require('./lib/example_templates_routes');
 
 // Set configuration variables

middleware/authentication.js → lib/middleware/authentication.js

@@ -1,5 +1,5 @@
 const url = require('url');
-const { encryptPassword } = require('../lib/utils');
+const { encryptPassword } = require('../utils');
 
 const allowedPathsWhenUnauthenticated = [
   '/prototype-admin/password',

middleware/prototype-admin-routes.js → lib/middleware/prototype-admin-routes.js

@@ -4,7 +4,7 @@ const router = express.Router();
 
 const password = process.env.PROTOTYPE_PASSWORD;
 
-const { encryptPassword } = require('../lib/utils');
+const { encryptPassword } = require('../utils');
 
 router.get('/password', (req, res) => {
   const returnURL = req.query.returnURL || '/';