Implement Software Upgrade Management API and Frontend Functionality

- Added software.php for managing software versions, including download and purchase actions.
- Created upgrade_paths.php for handling upgrade paths management.
- Developed user_licenses.php for managing user licenses.
- Introduced version_access_rules.php for managing access rules for software versions.
- Implemented frontend functions in functions.js for interacting with the software upgrade API.
- Added version_access.php for user access validation and license management.
- Created upgrades.php for displaying available upgrades and handling user interactions.
- Enhanced UI with responsive design and progress indicators for downloads and purchases.

settings/settingsmenu.php

@@ -281,6 +281,14 @@ $main_menu = [
             "icon" => "fas fa-tachometer-alt",
             "name" => "menu_profiles"  
         ]
+    ],
+    "upgrades" => [
+        "main_menu" => [
+            "url" => "upgrades",
+            "selected" => "upgrades",
+            "icon" => "fas fa-download",
+            "name" => "menu_upgrades"
+        ]
     ]
 ];