jsnbd: Create recipe and add it to the REST server

Create a recipe for the jsnbd repo and add a dependency to the
phosphor-rest-server app since it'll require it to run.
The same dependency will be added to bmcweb in a subsequent commit.

Tested: Verified the nbd-proxy binary is added to the image.

(From meta-phosphor rev: 59e96d7e66835f057838bf688e2fe8c642fd4588)

Change-Id: Id1c93a8d466c8622c0fc6a5a83e43334e4f541a5
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>