Import numpy in TubeCalibDemoMerlin_Adjustable.py re #8263

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Import numpy in TubeCalibDemoMerlin_Simple.py re #8263

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Remove TubeCalibDemoMerlin_Adjustable.py re #8263

This example is no longer needed. It demonstrated a withdrawn feature and was the example that no longer worked.

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Merge branch 'feature/8263_tube_calib_examples' into develop