Where is the Remote Desktop Session Host Configuration tool in Server 2012 ?

You can install just the Session Host role service and manage it entirely with PowerShell:

http://blogs.msdn.com/b/rds/archive/2012/06/28/introduction-to-windows-powershell-scripting-in-windows-server-2012-remote-desktop-services.aspx

You will eventually also need a License Server, which can be installed on the same Session Host or a separate sever entirely.

The RDS GUI management plug-in for Server Manager does require a domain in order to install. 

Don Geddes - SR Support Escalation Engineer - Remote Desktop Services - Printing and Imaging