Reduce120 demonstration

The goal is to demonstrate the following:

1. Upload an MD event file into history
2. Run the python code contained in the reduce120 notebook using this file as input
3. Generate MDHisto files as output that are added to the history
4. Download the MDHisto files to another location

The jupyter notebook to run in step 2 is:

/SNS/users/19g/notebooks/ARCS/get_dos_8_2021/reduce120.ipynb

Basically it takes a couple of event Nexus file loads them, processes them outputs MDHistoworkspaces. It also plots the workspaces that are output. In the same directory are the Data120.h5 and the MT120.h5