📖 [Story] Modularlizing TS core in Python

[narendasan]

TL;DR

Right now references to TS-Core (_C.so + deps) are all over the python package which makes pure python builds difficult. Some steps have been taken to move all references to TS-core into the TS subpackage so that TS can be an optional subpackage and not a requirement.

Goal(s)

Make it so that building pure python / TS-less packages is easy from the command line.

### Tasks
- [ ] https://github.com/pytorch/TensorRT/issues/2121

Additional context

[github-actions]

This issue has not seen activity for 90 days, Remove stale label or comment or this will be closed in 10 days