build main structure and build data layer and space managment bloc

lib/core/network/custom_exceptions.dart

@@ -0,0 +1,16 @@
+
+import 'enums.dart';
+
+class GenericException  implements Exception {
+  final ExceptionType type;
+  final String errorMessage;
+  const GenericException(
+      {required this.type, this.errorMessage = "Unknown Error"});
+
+  @override
+  String toString() {
+    return errorMessage;
+  }
+
+  List<Object?> get props => [type, errorMessage];
+}