add collectd resource node capability

add collectd resource node capability

allow manually adding collectd nodes using Node context.

if a node is present with a collectd config dict then
we can create a ResourceProfile object for it
and connect to collectd.

example

nodes:
-
    name: compute_0
    role: Compute
    ip: 1.1.1.1
    user: root
    password: r00t
    collectd:
        interval: 5
        plugins:
            ovs_stats: {}

Change-Id: Ie0c00fdb58373206071daa1fb13faf175c4313e0
Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>