Description of problem:
There's no reason we shouldn't do some sort of periodic ping checks and/or other diagnostics to get (and be able to provide) status of child nodes.

Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.  Set up a node on parent side but don't do requisite work on child side  
2.  katello --user admin --password admin node list
3.  view results.

Actual results:
We know the node exists from this query, but we know nothing about it.

Expected results:
We should be able to do at least one of a couple of things:
* have a "Status" column for the results in 'katello --user admin --password admin node list'
* be able to have a more robust query, i.e., 'katello --user admin --password admin node status --id 1'


Additional info:
Status could be any of "Responding, Unresponsive, Syncing" etc etc etc.