Cleans up runIsrTask.py and isrTask.py

Removed whitespace from isrTask.py.
Added missing import and cleaned up display
in runIsrTask.py.
Changes to use cameraGeomUtils to produce images

Before I was using some custom code to make the mocked images,
but there is code to do this in cameraGeomUtils.  I switched
to using that code.
Fixes DM-1196 to interpret read corner correctly

Read corners were erroneously set in assembled, but
they should actually be in raw coordinates.  This commit
fixes that.
Removes hard coded scaling

Calcules scaling for ds9 from the image rather than
hard coding the values.  This will make it less fragile
if the value in the mock data is changes.
Moves calculation of readcorner into function
Adds a comment explaing readcorner for amps