add COPYING file from tarball

Don't ship a separate COPYING file, since we can just get the COPYING
file from the tarball snapshot.

Signed-off-by: Ken Dreyer <ken.dreyer@inktank.com>
build and ship all three Ceph kmods

Build and ship packages for libceph, ceph, and rbd.

Signed-off-by: Ken Dreyer <ken.dreyer@inktank.com>
add more details to README

Signed-off-by: Ken Dreyer <ken.dreyer@inktank.com>