Signal quality notification %CESQ

The Nordic-proprietary %CESQ command subscribes notifications of changes in signal quality.v1.0.xv1.1.xv1.2.xv1.3.x

Note: When Narrowband Internet of Things (NB-IoT) system mode is used and the device is in RRC connected state, old signal quality parameter values are reported. The values are recorded and reported from the previous idle state.v1.0.xv1.1.xv1.2.x≤1v1.3.x