Revert "put .gitignore in the ASP.NET project folder"

This reverts commit c20bad2f8cdb16d3c426278a4a2b6d4f96d48769.
Revert "Revert "put .gitignore in the ASP.NET project folder""

This reverts commit ffb97816fd3f23e92938f8483a62b02614e4873f.