SCM GDA-5836 Update MaxiPix2MultiFrameDetector and MaxiPix2NexusDetector to work in 2d raster scans [needsw checkin on i13]

I'm not sure if the changes MaxiPix2NexusDetector were ultimetly required. The changes to MaxiPix2MultiFrameDetector definetely were.
Merge remote-tracking branch 'i13-1+gda+gda-scm/8.36' into 8.36