Add SCPI commands to store and return presets

[morgendagen]

Inspired by https://www.manson.com.hk/wp-content/uploads/2020/06/NEP_SCPI_command_list_1.0-for-Manson.pdf. Not sure if SYSTem:PRESet# is easily confused with SYSTem:PRESet.

SYSTem:PRESet# <voltage>，<current>, <ovp>, <ocp>

Description: Set values of preset program #. # is between 1 and 9. Voltage value unit is V|mV and Current value unit is A|mA

SYSTem:PRESet#?
Description: Return values of preset program#. # is between 1 and 9.