Bugfix/rzp 260009:Make MongoDB (pymongo) Optional via Poetry Extras

[Heisenberg208]

Description

This PR makes pymongo an optional dependency instead of a required one.
MongoDB support is now enabled via a Poetry extra (mongo) and the application gracefully handles cases where MongoDB is not installed or unavailable

Fixes #9 (issue)

Type of change

Please delete options that are not relevant.

• [✅ ] Bug fix (non-breaking change which fixes an issue)
• [ ✅ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist

• [ ✅ ] My code follows the style guidelines of this project
• [ ✅ ] I have performed a self-review of my own code
• [ ✅ ] I have commented my code, particularly in hard-to-understand areas
• [ ✅ ] I have made corresponding changes to the documentation