Add HostFiltering configuration to templates

Commit migrated from dotnet/aspnetcore@f25f411b68

src/Microsoft.DotNet.Web.Spa.ProjectTemplates/content/Angular-CSharp/appsettings.json

@@ -3,5 +3,6 @@
     "LogLevel": {
       "Default": "Warning"
     }
-  }
+  },
+  "AllowedHosts": [ "*" ]
 }

src/Microsoft.DotNet.Web.Spa.ProjectTemplates/content/React-CSharp/appsettings.json

@@ -3,5 +3,6 @@
     "LogLevel": {
       "Default": "Warning"
     }
-  }
+  },
+  "AllowedHosts": [ "*" ]
 }

src/Microsoft.DotNet.Web.Spa.ProjectTemplates/content/ReactRedux-CSharp/appsettings.json

@@ -3,5 +3,6 @@
     "LogLevel": {
       "Default": "Warning"
     }
-  }
+  },
+  "AllowedHosts": [ "*" ]
 }