Add Uptrain Callback Handler (#10432)

* Add UpTrain Callback Handler

* Add logging

* Add note for project_name prefix

* Minor fixes

* Add explanations

* Add showcase

* Add callback to uptrain.md

* update import

* linter

* Update .gitignore file to ignore .venv and __pycache__ directories

* Fix imports

* create llama-index-callback-uptrain

* Update UpTrainCallback.ipynb

* Update README.md

* Run pants tailor