fix: update formatting and DOM manipulation in SimpleCheckout.js

This commit implements minor refactoring changes in the SimpleCheckout.js file.

• Updated formatting to include space before function parameters across multiple method declarations for improved readability.
• Modified DOM manipulation logic to use data-name attribute instead of class name for element selection, enhancing selection accuracy.
• Added data-name attribute set command to retain DOM element specific data when replacing HTML.
• Improvements in 'require' callbacks to use fat arrow function notation.
• Minor adjustments in formatting in methods dealing with Events and DOM manipulations.

Related: coupons#19 (closed)

src/QUI/ERP/Order/SimpleCheckout/Steps/CheckoutBillingAddress.html

@@ -2,7 +2,7 @@
     <input type="radio" name="billing_address" value="same_as_shipping" checked/>
     <span>
         {locale group="quiqqer/order-simple-checkout" var="ordering.step.title.Billing.same"}
-    </span>s
+    </span>
 </label>
 <label class="quiqqer-simple-checkout-billing__entry">
     <input type="radio" name="billing_address" value="different"/>