OpenBMC power supply monitoring application.
Design document: https://github.com/openbmc/docs/blob/master/designs/psu-monitoring.md
The JSON configuration file should contain:
Optional property, integer, that indicates the minimum number of power supplies that should be present.
Optional property, integer, that indicates the maximum number of power supplies that should be present.
An array of power supply properties.
The D-Bus path used to check the power supply presence (Present) property.
An integer specifying the I2C bus that the PMBus power supply is on.
A string representing the 16-bit I2C address of the PMBus power supply.