Refactor network API calls to use centralized authentication context and improve cache handling

- Removed redundant getApiToken function and replaced its usage with getAuthContext in network-api.js, network-events.js, and network-init.js.
- Updated cache handling in network-events.js and network-init.js to use CACHE_KEYS constants for better maintainability.
- Introduced cache.js for centralized cache management functions and constants, including cache initialization and retrieval.
- Added app-init.js for application lifecycle management, including cache orchestration and initialization checks.
- Created app_config.php to securely fetch API token and GraphQL port from configuration.
- Improved error handling and logging throughout the codebase for better debugging and maintenance.

front/deviceDetailsTools.php

@@ -526,13 +526,7 @@
         function getVisibleDevicesList()
         {
             // Read cache (skip cookie expiry check)
-            devicesList = getCache('devicesListAll_JSON', true);
-
-            if (devicesList != '') {
-                devicesList = JSON.parse (devicesList);
-            } else {
-                devicesList = [];
-            }
+            devicesList = parseDeviceCache(getCache('devicesListAll_JSON', true));
 
             // only loop thru the filtered down list
             visibleDevices = getCache("ntx_visible_macs")