Track NIR readout serial numbers

The visible DAQ chain saves the FEE, ADC, preamp, detectors serial numbers in the FEE NVRAM, and folks are pretty/very good about maintaining that. The FEE serial number can be read back and so provides the "root".

We need the same for the NIR chain: SAM, cable, ASIC, cable, H4 ROIC. There is no place to save that, but we can at least read back the SAM serial number.

So pfs_instdata/data/hx/$camera/daqConfig.yaml unless voted down. "hx" because the main writer is the "hxActor". Have a "serials" section with the obvious slots.