Bug#779970: update

[Paolo Greppi <paolo.greppi@libpf.com>]

In the meantime .NET Core 2.0:
https://blogs.msdn.microsoft.com/dotnet/2017/08/14/announcing-net-core-2-0/
and it is a requirement for powershell 6.0:
https://blogs.msdn.microsoft.com/powershell/2018/01/10/powershell-core-6-0-generally-available-ga-and-supported/

Based on the suggestions for package naming:
https://github.com/dotnet/docs/blob/master/docs/core/build/distribution-packaging.md
it looks like the two ITPs should probably be merged into one named "dotnet".

Building from source is supported by upstream:
https://github.com/dotnet/docs/blob/master/docs/core/build/index.md
but one issue to solve before this can be packaged is that currently the build script downloads stuff from the network:
https://github.com/dotnet/coreclr/issues/9696

Paolo