Add helpers for boolean functions

lib/api.dart

@@ -1365,6 +1365,12 @@ class InvenTreeAPI {
     }
   }
 
+  // Return a boolean global setting value
+  Future<bool> getGlobalBooleanSetting(String key) async {
+    String value = await getGlobalSetting(key);
+    return value.toLowerCase() == "true";
+  }
+
   Future<String> getUserSetting(String key) async {
     if (!supportsSettings) return "";
 
@@ -1385,6 +1391,12 @@ class InvenTreeAPI {
     }
   }
 
+  // Return a boolean user setting value
+  Future<bool> getUserBooleanSetting(String key) async {
+    String value = await getUserSetting(key);
+    return value.toLowerCase() == "true";
+  }
+
   /*
    * Send a request to the server to locate / identify either a StockItem or StockLocation
    */