Use the gNB-DU configuration update to signal the cell status in the
stack. At the DU, modify the code to always send this message --
previously, we only sent this message if a SIB1 update was necessary,
but now it's always, only including SIB1 updates if necessary.
At the CU, as we don't really have a use as of now, print the
information, but don't do anything with it.