Introducing Bridge Operational State

And using it for Bridge/TerminationPoint Delete Operations

In order to correctly handle 'merge' of data on update
we will need the BridgeOperationalState functionality,
so we can know what we *have* and thus whether to do
an insert/update/mutate.

Change-Id: I9e5200bf1b7f724e346b0855c32f6510773f5e5d
Signed-off-by: Ed Warnicke <eaw@cisco.com>