SoC: Project page ready

I've just set up the NetBSD-SoC: Efficient memory file-system project page. At the moment, it includes a list of the project goals, a copy of the original proposal text (in case you would like to read it) and a list of existing documentation.

This page will be extended to hold technical information as well as installation instructions (that is, how to merge the code in that page with NetBSD's source tree) when the project matures during the summer.