gNB: apply new NR_CellGroupConfig when RRCReconfiguration is acknowledged

Currently part of the NR_CellGroupConfig is already applied when the RRCReconfiguration message is created. This is not correct and this MR fixes this by applying it when the RRCReconfiguration message is acknowledged.

With this fixed, we also move disabling the feedback (in case disable_harq is used) from the RRCSetup message to the RRCReconfiguration message.

Also closes #1002