Adds db helper requsts for flights pertaining to drones/batteries, and config class with generated json serializer

lib/generated/config.g.dart

@@ -0,0 +1,13 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of '../config.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+RTimeConfig _$RTimeConfigFromJson(Map<String, dynamic> json) =>
+    RTimeConfig(language: json['language'] as String);
+
+Map<String, dynamic> _$RTimeConfigToJson(RTimeConfig instance) =>
+    <String, dynamic>{'language': instance.language};