Init login feature add domain layer

lib/features/login/domain/exceptions/authentication_exception.dart

@@ -0,0 +1,14 @@
+import 'package:equatable/equatable.dart';
+
+abstract class AuthenticationException extends Equatable {
+  static final wrongCredential = 'Credential is wrong';
+
+  AuthenticationException(String message);
+}
+
+class BadCredentials extends AuthenticationException {
+  BadCredentials() : super(AuthenticationException.wrongCredential);
+
+  @override
+  List<Object> get props => [];
+}