OSS Version of memorization of online content tutorial w/ gpt-oss-20b (#88)

Summary:
Pull Request resolved: #88

This tutorial adds the online content memorization tutorial to the Github OSS repo in the Jupyter notebook format (.ipynb)

The tutorial focuses on performing text extraction attacks on gpt-oss-20b, with common online text content.

Reviewed By: lucamelis

Differential Revision: D88642974

fbshipit-source-id: 26bafd5c4ee4387132b272922b8fe22ab420a330

Author: mgrange1998