Allow read-adc without MonitorV address
The read-adc executable requires user to specify the MonitorV value that they want to read (https://gitlab.cern.ch/YARR/YARR/-/blob/master/src/tools/read-adc.cpp#L30). But it would be nice to just read the ADC with whatever is the current setting of MonitorV. I would suggest that MonitorV is included as an option instead of a required argument. This would be useful for using the calibrated ADC instead of the Vmux in QC-tools (https://gitlab.cern.ch/atlas-itk/pixel/module/module-qc-tools/-/merge_requests/108).