Remove IAbpApplication for now.

src/Volo.Abp.AspNetCore/Abp/AspNetCore/AbpApplicationBuilderExtensions.cs

@@ -8,7 +8,7 @@ namespace Microsoft.AspNetCore.Builder
     {
         public static void InitializeAbpApplication(this IApplicationBuilder app) //TODO: Simply rename to InitializeApplication?
         {
-            var abpApplication = app.ApplicationServices.GetRequiredService<IAbpApplication>();
+            var abpApplication = app.ApplicationServices.GetRequiredService<AbpApplication>();
 
             app.ApplicationServices.GetRequiredService<ApplicationBuilderAccessor>().App = app;
 

src/Volo.Abp/Abp/AbpApplication.cs

@@ -4,7 +4,7 @@ using Volo.Abp.Modularity;
 
 namespace Volo.Abp
 {
-    public class AbpApplication : IAbpApplication
+    public class AbpApplication : IDisposable
     {
         public Type StartupModuleType { get; }
 
@@ -14,7 +14,7 @@ namespace Volo.Abp
         {
             StartupModuleType = startupModuleType;
             
-            services.AddSingleton<IAbpApplication>(this);
+            services.AddSingleton(this);
             services.AddCoreAbpServices();
 
             services.GetSingletonInstance<IModuleLoader>().LoadAll(services, StartupModuleType);

src/Volo.Abp/Abp/IAbpApplication.cs

@@ -1,11 +0,0 @@
-using System;
-
-namespace Volo.Abp
-{
-    public interface IAbpApplication : IDisposable
-    {
-        Type StartupModuleType { get; }
-
-        void Initialize(IServiceProvider serviceProvider);
-    }
-}