Where to put app.config in Power BI RS

I have read that issue which describes the issue quite well. #187
Still there is no resolution where to put that file. With Power BI Report Server it might be a different location.

It seems that hard-coded values are in Settings.Designer.cs, however, they should be overwritten by an app.config which is also in this repo.

While other config settings are done automatically in Configure.ps1 there is no handling of app.config.