[build] Add csharp script to build the list of referenced source file in the csproj
[build] Add csharp script to build the list of referenced source file in the csproj

This is to be used to generate the corresponding list in Makefile.am mainly to have a correct make dist target

openmedicus/dbus-sharp,mono/dbus-sharp,mono/dbus-sharp,Tragetaschen/dbus-sharp,arfbtwn/dbus-sharp,arfbtwn/dbus-sharp,openmedicus/dbus-sharp,Tragetaschen/dbus-sharp