SXD: OPI for Compact Focussing Device (PM600)

As a SXD scientist I want to be able to control the compact focussing device, so that I can control the beam.

**Note:** it is quite possible that this ticket will not be needed - the compact focussing device has never been used since it was originally installed (see notes below).

#### Acceptance Criteria
1. Using the IBEX client, I can control the compact focussing device.
1. Using the genie_python, I can control the compact focussing device.

#### Notes
1. Check the [SXD Instrument wiki](https://github.com/ISISComputingGroup/IBEX/wiki/SXD-Instrument-Details).
1. The OPI must offer functionality equivalent to the existing VI (located here: `C:\LabVIEW Modules\Instruments\SXD\SXD Compact Focusing Device`).
* The Compact Focussing Device is controlled by McLennan drives (PM600).
1. **Note from Instrument Scientist:**
* The compact focussing device refers to a motorised mount that is permanently installed on SXD.
* It was only used for testing and never since.
* This focussing device is a compact supermirror guide, called a trumpet, with a length of 390mm and a rectangular cross section going from 15x15mm at the entrance down to 5x5mm at the exit.
* The mount has x, y translation and horizontal and vertical angular adjustment. There was also translation along the beam but this was removed since it caused the entire setup to droop.