Add KIKUSUI PCR500MA AC power supply agent

[dixilo]

Description

This pull request adds a new agent to operate KIKUSUI's PCR500MA AC power supply.

Motivation and Context

PCR500MA will be used as a power source to the stimulator heater to generate radiation.
Since the device will be connected to the site ethernet and be controlled from daq-pc, it should be included in this socs repository.

How Has This Been Tested?

Test was done using the actual PCR500MA device.
The device was connected to the lab network, and the ocs agent and client were run from a PC also connected to the same network.
Functions in the agent code was tested by checking the display and the light indicator of the device.
Torelance to the ethernet disconection was also tested by just unplugging the cable from the device.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[BrianJKoopman]

This looks great, thanks for the PR! A few small comments below. I'm also going to push a commit with some packaging bits. Please pull before making further changes.