Remove LoadDetectorInfo from DirectEnergyConversion.py script

[martyngigg]

The algorithm does the following:

• updates detector positions based on input file positions;
• sets component parameters for the tube pressure & wall thickness and
• adjusts X bins by a detector delay time.

This behaviour needs splitting up. The tube pressure, wall thickness should be in the instrument definition (much as the SNS instruments do now), along with the detector delay time. The UpdateInstrumentFromFile algorithm already accepts RAW,ISIS Nexus and others. It simply needs extending to read the block from an ISIS event nexus file.

[martyngigg]

This issue was originally trac ticket 8057