bug/1271377 change NetworkGroup.name to String(50)

Change-Id: Iec333c70a799b1be945bd0f212f0a82c0f779222
Assign 1 admin IP per node

Change-Id: If64e4a3e6f13b32f13293507f83626104ae9bcd9
Fix Ubuntu to use MAC instead of arbitrary iface name

Change-Id: Ie3bed8de63fbb38edc9d08727100238178c83d09
Add fallback test in __check_interfaces_correctness

In some cases, it may be OK for there to be an admin interface
 that is outside the admin network. To support this case we we will
 test if the interface mac matches the mac that contacted us, if this
 is the case, we will use this interface.

This prevents the NetworkManager from erroneously removing interfaces
 from an otherwise valid node.

Resolves-bug: #1271043

Change-Id: I04120d538e2efba6cb7a04cfbd7cb4852f2576c9