polref: get laser button working

[rerpha]

as a polref scientist i would like the button that says turn laser off/on on the polref reflectometry front panel to work properly.

acceptance criteria

• [x] button turns the laser on and off

[rerpha]

have added the background script to their base component, need to go down and see if the buttons work

[rerpha]

this involved adding the background script IOC to polref's base config. to review check it's in there and running