added docs for process_manager.py

[bashirk]

Description

This PR adds inline documentation to the process_manager.py file.

Relevant Issue

Issue #269

Checklist

• [x] I have followed the Contribution Guidelines and Code of Conduct
• [x] I have commented my code following the NimbleEdge Styleguide

[netlify[bot]]

✅ Deploy Preview for goofy-agnesi-4565cb canceled.

Name	Link
🔨 Latest commit	00c4bf884c18dd7226ebe8741ff0abdd08603766
🔍 Latest deploy log	https://app.netlify.com/sites/goofy-agnesi-4565cb/deploys/62fb263a2cd0c10007445ad7

[divyanshugit]

LGTM!! @ramesht007