Implement LACP validation

[craiganderson]

1. Verify that each bond interface member is Up and that the link status is also Up for each bond member
2. Successful ping test to gateway or other IP over LACP bond
3. ethtool run on each bond shows proper aggregate Speed for link
4. for each LACP bond member, ensure Aggregator ID, port key, and oper key match within the scope of that port channel
5. Detect / report error condition where switches are misconfigured for Cisco etherchannel (default link aggregation mode for Cisco switches)