simple and generic trx_write support of out of time order requests and removal of RX/TX min in the UE

This MR creates a new RF board write function that handle out of order slots
we may use it also in the gNB later

This MR removes the RX/TX min in the UE, it only assumes the TX information to send can't come after RX slot +2, as per the standard Then, we can have real time issues

In this MR, there is also a cleanup of the nr_initial_sync() function, but it is only a intermediate step