superpmi.py script improvements (#42773)

superpmi.py script improvements (#42773)

1. Make the script pylint and pycodestyle clean (with exclusions).
Add pylint/pycodestyle configuration files.

2. Simplify and remove duplication in asm diffs code for generating
asm and JIT dump files.

3. Add cases to automatically upload and download associated .MCT files
if one or more specific .MCH files are specified.

4. Fix a few bugs related to using VS Code to view diffs. (I'm inclined
to remove this complication entirely unless someone actually uses it.)