WIP: Transition AgilentPs's to one class per model.

Changes the IPowerSupply implementation naming to one power supply model per class. The motivation is to make it easier to user to identify the required implementation and to reduce the ambiguity in naming.

Modifications are:

• Renamed Agilent PS's that had multiple models per class. The AgilentPs itself still supports multiple models.
• Updated Python bindings.
• Updated documentation.

WIP:

• Rename DT54xxPs and Bk16XXPs.