Implement SCPI Status commands

[M1S2]

Implement the commands of the SCPI Status subsystem.

PowerSupply QUEStionable (taken from https://www.ivifoundation.org/docs/scpi-99.pdf Page 794):
For a power supply, the bits of interest in the QUEStionable status structure are VOLTage and CURRent. When a power supply is operating as a voltage source, bit 1 (CURRent) shall be set. When a power supply is operating as a current source, bit 0 (VOLTage) shall be set. When the output is unregulated, both bits shall be set (for example, while the output is changing to a new programmed value).