staging: ramster: place ramster codebase on top of new zcache2 codebase

This slightly modified ramster codebase is now built entirely on zcache2
and all ramster-specific code is fully contained in a subdirectory.

Ramster extends zcache2 to allow pages compressed via zcache2 to be
"load-balanced" across machines in a cluster.  Control and data communication
is done via kernel sockets, and cluster configuration and management is
heavily leveraged from the ocfs2 cluster filesystem.