Improved handling of moonlight plugins during startup, minimized host project code and moved startup handling to core

Hosts/Moonlight.Frontend.Host/Program.cs

@@ -1,20 +1,9 @@
-using Microsoft.AspNetCore.Components.WebAssembly.Hosting;
-using Moonlight.Frontend.Startup;
+using Moonlight.Frontend;
 using SimplePlugin.Generated;
 
-var modules = PluginRegistry
+var plugins = PluginRegistry
     .Modules
-    .OfType<IAppStartup>()
+    .OfType<MoonlightPlugin>()
     .ToArray();
 
-var builder = WebAssemblyHostBuilder.CreateDefault(args);
-
-foreach (var startup in modules)
-    startup.PreBuild(builder);
-
-var app = builder.Build();
-
-foreach(var startup in modules)
-    startup.PostBuild(app);
-
-await app.RunAsync();
+await StartupHandler.RunAsync(args, plugins);