BFD-related workflow steps

If trunk_type is Leased, then BFD must be configured on that trunk according to the policy. The steps that are added will update the target loopback address of BFD config on the remaining side when trunk type is Leased, and will be skipped when trunk type is Dark_fiber.

test/fixtures.py

@@ -279,7 +279,6 @@ def iptrunk_subscription_factory(iptrunk_side_subscription_factory, faker, geant
         start_date="2023-05-24T00:00:00+00:00",
         geant_s_sid=None,
         iptrunk_description=None,
-        # iptrunk_type=IptrunkType.DARK_FIBER,
         iptrunk_type=IptrunkType.LEASED,
         iptrunk_speed=PhysicalPortCapacity.ONE_GIGABIT_PER_SECOND,
         iptrunk_isis_metric=None,