Project code support (#336)

* Determine if project codes are supported

* Add helpers for boolean functions

* Adds helper methods for generic "model" class

- Will allow us to do some good refactoring

* Refactor the refactor

* Add debug support and getMap function

* Major refactoring for model data accessors

* Handle null values

* Add sentry reporting if key is used incorrectly

* Fix typo

* Refactor createFromJson function

* Add model for ProjectCode

* Display and edit project code for purchase orders

lib/api.dart

@@ -300,6 +300,9 @@ class InvenTreeAPI {
   // Order barcodes API v107 or newer
   bool get supportsOrderBarcodes => isConnected() && apiVersion >= 107;
 
+  // Project codes require v109 or newer
+  bool get supportsProjectCodes => isConnected() && apiVersion >= 109;
+
   // Are plugins enabled on the server?
   bool _pluginsEnabled = false;
 
@@ -1362,6 +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 "";
 
@@ -1382,6 +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
    */