feat: openfoodfacts#370 - new source configuration for saveProduct

New file:
* `SourceConfiguration.dart`: Source Configuration for detection of apps (populates data sources on BE).

Impacted file:
* `openfoodfacts.dart`: added source configuration parameter to `saveProduct`

lib/openfoodfacts.dart

@@ -27,6 +27,7 @@ import 'package:openfoodfacts/utils/PnnsGroups.dart';
 import 'package:openfoodfacts/utils/ProductFields.dart';
 import 'package:openfoodfacts/utils/ProductListQueryConfiguration.dart';
 import 'package:openfoodfacts/utils/QueryType.dart';
+import 'package:openfoodfacts/utils/SourceConfiguration.dart';
 import 'package:openfoodfacts/utils/TagType.dart';
 import 'package:openfoodfacts/utils/TaxonomyQueryConfiguration.dart';
 import 'package:openfoodfacts/utils/UriHelper.dart';
@@ -81,6 +82,7 @@ export 'utils/ProductFields.dart';
 export 'utils/ProductHelper.dart';
 export 'utils/ProductQueryConfigurations.dart';
 export 'utils/ProductSearchQueryConfiguration.dart';
+export 'utils/SourceConfiguration.dart';
 
 /// Client calls of the Open Food Facts API
 class OpenFoodAPIClient {
@@ -92,15 +94,19 @@ class OpenFoodAPIClient {
   /// Please read the language mechanics explanation if you intend to display
   /// or update data in specific language: https://github.com/openfoodfacts/openfoodfacts-dart/blob/master/DOCUMENTATION.md#about-languages-mechanics
   static Future<Status> saveProduct(
-    User user,
-    Product product, {
-    QueryType? queryType,
+    final User user,
+    final Product product, {
+    final QueryType? queryType,
+    final SourceConfiguration? sourceConfiguration,
   }) async {
-    var parameterMap = <String, String>{};
+    final Map<String, String> parameterMap = <String, String>{};
     parameterMap.addAll(user.toData());
     parameterMap.addAll(product.toServerData());
+    if (sourceConfiguration != null) {
+      parameterMap.addAll(sourceConfiguration.getParameters());
+    }
 
-    var productUri = UriHelper.getUri(
+    final Uri productUri = UriHelper.getUri(
       path: '/cgi/product_jqm2.pl',
       queryType: queryType,
     );

lib/utils/SourceConfiguration.dart

@@ -0,0 +1,26 @@
+/// Source Configuration for detection of apps (populates data sources on BE).
+class SourceConfiguration {
+  const SourceConfiguration({
+    this.appName,
+    this.appVersion,
+    this.appUuid,
+  });
+
+  final String? appName;
+  final String? appVersion;
+  final String? appUuid;
+
+  Map<String, String> getParameters() {
+    final Map<String, String> result = <String, String>{};
+    if (appName != null) {
+      result['app_name'] = appName!;
+    }
+    if (appVersion != null) {
+      result['app_version'] = appVersion!;
+    }
+    if (appUuid != null) {
+      result['app_uuid'] = appUuid!;
+    }
+    return result;
+  }
+}