Default Identity UI to Bootstrap4

src/Microsoft.DotNet.Web.ProjectTemplates/content/RazorPagesWeb-CSharp/Startup.cs

@@ -18,6 +18,7 @@ using Microsoft.AspNetCore.Authentication.AzureADB2C.UI;
 using Microsoft.AspNetCore.Builder;
 #if (IndividualLocalAuth)
 using Microsoft.AspNetCore.Identity;
+using Microsoft.AspNetCore.Identity.UI;
 #endif
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Http;
@@ -69,6 +70,7 @@ namespace Company.WebApplication1
                     Configuration.GetConnectionString("DefaultConnection")));
 #endif
             services.AddDefaultIdentity<IdentityUser>()
+                .AddDefaultUI(UIFramework.Bootstrap4)
                 .AddEntityFrameworkStores<ApplicationDbContext>();
 
 #elif (OrganizationalAuth)

src/Microsoft.DotNet.Web.ProjectTemplates/content/StarterWeb-CSharp/Startup.cs

@@ -18,6 +18,7 @@ using Microsoft.AspNetCore.Authentication.AzureADB2C.UI;
 using Microsoft.AspNetCore.Builder;
 #if (IndividualLocalAuth)
 using Microsoft.AspNetCore.Identity;
+using Microsoft.AspNetCore.Identity.UI;
 #endif
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Http;
@@ -69,6 +70,7 @@ namespace Company.WebApplication1
                     Configuration.GetConnectionString("DefaultConnection")));
 #endif
             services.AddDefaultIdentity<IdentityUser>()
+                .AddDefaultUI(UIFramework.Bootstrap4)
                 .AddEntityFrameworkStores<ApplicationDbContext>();
 #elif (OrganizationalAuth)
             services.AddAuthentication(AzureADDefaults.AuthenticationScheme)