Shift ukwelcomes.businesslink.gov.uk to be managed by transition

In addition to this site now being managed by transition, this pull request removes the specialised config required for this domain from redirector.

It assumes that the WorldPayCallback URL proxy pass (with paths like ```/eff/action/worldPayCallback?installation=254078&msgType=authResult``` is maintained in Bouncer, or rendered unnecessary by changes in Local Authority systems.