Draft: Add ISEG PS support

This MR adds support for ISEG HV powersupplies.

Command protocol: https://iseg-hv.com/download/SOFTWARE/isegSCPI/SCPI_Programmers_Guide_en.pdf

The implementation is based on an example python file for the ISEG SHR 2020 supplies provided by @mbaselga.

It is still a draft, as functional validation is still missing.

@mbaselga to validate this PS implementation, please do the following on your lab computer:

1. Clone the repo (@mbaselga, you are the only one with the appropriate rights)

   git clone --recursive https://gitlab.cern.ch/bbrueers/labRemote.git --branch addIsegPs
   cd labRemote

2. Build the code

   mkdir build
   cmake ..
   make
   cd ..

3. Connect the powersupply to your lab computer in your desired way (preferentially via USB as will be with the mass tester).
4. Create a new equip-testbench.json. This is a config file in which you define the powersupply to be used. Follow e.g. the example here. In the HV PS part, you will have to use as hw-model the type IsegSHR20xxPs. You will also have to fill in the details about termination, baud-rate, communications port, etc.
5. In the labRemote folder run

   ./build/bin/powersupply -n HV -c <channel-number> <command>

   Please test all available commands, see by typing ./build/bin/powersupply -h which ones are available.