Fix admin route access and backend configuration

- Added /admin redirect to login page in nginx config
- Fixed backend server.js route ordering for proper admin handling
- Updated authentication middleware and routes
- Added user management routes
- Configured PostgreSQL integration
- Updated environment configuration

Services/MongoDBSettings.cs

@@ -0,0 +1,12 @@
+using System.Collections.Generic;
+
+namespace SkyArtShop.Services;
+
+public class MongoDBSettings
+{
+	public string ConnectionString { get; set; } = string.Empty;
+
+	public string DatabaseName { get; set; } = string.Empty;
+
+	public Dictionary<string, string> Collections { get; set; } = new Dictionary<string, string>();
+}