Add minus to HV at 0V to set polarity right for ISEG PSs

The ISEG HV PSs need a dedicated polarity setting. As implementing a SetPolarity function on IPowerSupply level would have resulted in warnings for dozens of PSs, it was decided to set the polarity by the sign of the set voltage when the PS is off.

This is what this MR addresses. The voltage is set to -0V when the HV PS is off in the HVenable test.

Also, this MR updates the labremote version to include ISEG PSs.

Tagging @mbaselga @tbisanz