CMOR MODIS Update

[noahfruttarol]

I was tasked with updating the MODIS cmorization script at my work,

The update that we already had internally:

• Separate script for MODIS terra as it has a different version and file format and version (aqua version: MYD08_M3, terra version: MOD08_M3)
• Variable reffclwtop added to script.

The changes I made:

• Remake as a python script as NCL is no longer supported and this will make future additions easier.
• Update the scripts to CMIP6.

These changes can be seen on a branch here: https://github.com/noahfruttarol/ESMValTool/tree/MODIS_cmorize_update

Also, I am unsure what to do with the deprecated NCL scripts I currently just left at ESMValTool/esmvaltool/cmorizers/data/formatters/datasets/_modis_aqua.ncl
ESMValTool/esmvaltool/cmorizers/data/formatters/datasets/_modis_terra.ncl

[noahfruttarol]

I am going to expand the variables that are cmorized next