CBQE-1261: support for 'remote' flag in xdcr test specs

When 'remote' is used in a test spec then a remote phase is created and sent to remote site and monitored locally.
This is primarily for xdcr use cases
{
    "name" : "simple_load",
    "desc" : "load items at 1k ops",
    "workload" : {"spec" : "s:100,ccq:simplekeys,ops:1000",
    "remote" : "10.0.0.11"},
    "template" : "default",
    "runtime" : 20
},

Change-Id: I12c2acff35be603075351b3ba6f762bff4f55e6e
Reviewed-on: http://review.couchbase.org/26069
Reviewed-by: Chisheng Hong <chisheng@couchbase.com>
Tested-by: Tommie McAfee <tommie@couchbase.com>