Refactor division operations to use native Python 3 semantics

[shankari]

• Transition from old_div to native division across the codebase, ensuring consistent behavior in division operations. This change finally finishes up the migration with Python 3 from 10 years ago and makes the code easier to read. We have added one test to capture a branch that was modified but not covered previously.
  • The transition was staged in batches to make it easier to identify and fix any regressions
• Remove unused files

TODO:

• there is a bad condition in cfc_webapp.py

if round((duration - new_duration) / new_duration > 100) > 0:

That has been around forever; we should fix that in the next round