Refactor billing form templates and improve error handling

- Updated billing code label from "Kod" to "Kod pocztowy" for clarity.
- Enhanced error message handling in createFirstUserDataSuccess.php for better user feedback.
- Removed deprecated userdata_order_form.html and userdata_order_form_billing.html.bck templates.
- Adjusted layout in userdata_order_form.html for better responsiveness.
- Added input formatting for postal code in userdata_order_form.html to enforce correct input format.

.vscode/ftp-kr.sync.cache.json

@@ -3,12 +3,6 @@
     "domains": {
       "grzanieplus.pl": {
         "public_html": {
-          ".gitignore": {
-            "type": "-",
-            "size": 32,
-            "lmtime": 0,
-            "modified": false
-          },
           "apps": {
             "frontend": {
               "modules": {
@@ -1578,8 +1572,8 @@
                     },
                     "one_column.html": {
                       "type": "-",
-                      "size": 2730,
-                      "lmtime": 1725624369265,
+                      "size": 3068,
+                      "lmtime": 1748290022761,
                       "modified": false
                     },
                     "two_column.html": {
@@ -3814,6 +3808,12 @@
           },
           "doc": {},
           "fastcache": {},
+          ".gitignore": {
+            "type": "-",
+            "size": 32,
+            "lmtime": 0,
+            "modified": false
+          },
           "install": {},
           "lib": {},
           "log": {},