Add monitoring and protection for FMC voltages and currents

Inspired by https://gitlab.cern.ch/be-cem-edl/fec/hardware-modules/fmc-mfe/-/issues/19, the idea is to monitor 12V, 3V3 and Vadj going to the FMC. Ideally we read the FMC EEPROM at boot time using 3V3AUX, retrieve the power requirements of the FMC module, program our monitoring circuits and then enable power to the FMC. If the FMC module does not provide this information, we roll back to some sensible defaults, below our maximum capability.