Disable inclusion of IIS hosting assets (ANCM & web.config) in publish output when PublishNativeAot=true

[DamianEdwards]

When publishing for Windows today, the web SDK includes assets required to run the project on IIS, namely the ANCM module (aspnetcorev2_inprocess.dll) and a web.config file. As part of the work to support native AOT publish for ASP.NET Core, we should ensure that these assets are not included in the application output when the <PublishAot> property is set to true in the project file, as IIS hosting does not support native AOT published ASP.NET Core apps, i.e. set the default value of <PublishIISAssets> to false when <PublishAot> is true.