Remove unused `using`-s from Program and Startup classes

Commit migrated from dotnet/aspnetcore@8c287bc7e5

src/content/Angular-CSharp/Program.cs

@@ -1,12 +1,9 @@
 using System;
 using System.Collections.Generic;
-using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore;
 using Microsoft.AspNetCore.Hosting;
-using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.Logging;
 
 namespace Company.WebApplication1
 {

src/content/Angular-CSharp/Startup.cs

@@ -10,7 +10,6 @@ using Microsoft.AspNetCore.Identity.UI;
 #if (RequiresHttps)
 using Microsoft.AspNetCore.HttpsPolicy;
 #endif
-using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.SpaServices.AngularCli;
 #if (IndividualLocalAuth)
 using Microsoft.EntityFrameworkCore;

src/content/React-CSharp/Program.cs

@@ -1,12 +1,9 @@
 using System;
 using System.Collections.Generic;
-using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore;
 using Microsoft.AspNetCore.Hosting;
-using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.Logging;
 
 namespace Company.WebApplication1
 {

src/content/React-CSharp/Startup.cs

@@ -10,7 +10,6 @@ using Microsoft.AspNetCore.Identity.UI;
 #if (RequiresHttps)
 using Microsoft.AspNetCore.HttpsPolicy;
 #endif
-using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.SpaServices.ReactDevelopmentServer;
 #if (IndividualLocalAuth)
 using Microsoft.EntityFrameworkCore;