feat(data): create initial DatabaseSeedingService class

Adds the foundational `DatabaseSeedingService` class. This service will be responsible for all database schema creation and data seeding operations.

Author: fulleni

lib/src/services/database_seeding_service.dart

@@ -0,0 +1,24 @@
+import 'package:logging/logging.dart';
+import 'package:postgres/postgres.dart';
+
+/// {@template database_seeding_service}
+/// A service responsible for initializing the database schema and seeding it
+/// with initial data.
+///
+/// This service is intended to be run at application startup, particularly
+/// in development environments or during the first run of a production instance
+/// to set up the initial admin user and default configuration.
+/// {@endtemplate}
+class DatabaseSeedingService {
+  /// {@macro database_seeding_service}
+  const DatabaseSeedingService({
+    required Connection connection,
+    required Logger log,
+  }) : _connection = connection,
+       _log = log;
+
+  final Connection _connection;
+  final Logger _log;
+
+  // Methods for table creation and data seeding will be added here.
+}