web: add basic ASP.NET Core web interface

PluralKit.Web/Program.cs

@@ -0,0 +1,19 @@
+using Microsoft.AspNetCore;
+using Microsoft.AspNetCore.Hosting;
+
+namespace PluralKit.Web
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            CreateWebHostBuilder(args).Build().Run();
+        }
+
+        public static IWebHostBuilder CreateWebHostBuilder(string[] args)
+        {
+            return WebHost.CreateDefaultBuilder(args)
+                .UseStartup<Startup>();
+        }
+    }
+}