Feat: context parallel v2.0 (#3700)
* Cleanup: context parallel
* Feat: cleanup
* Feat: concept guide
* Fix: rename + version check
* Style
* Fix: add to namespace in a test
* Fix: add skip_if on dataclass tests
* Fix: proper version for version check
* Feat: add tests and cleanup
* Fix: properly version check added tests
* Feat: address comments
* Fix: add both shift_labels and labels to make the model.forward calculate loss
* Fix: remove import, improve comment
* Fix: final checks
* Fix: style
* Fix: style
