Computation based evaluation for text bison deprecation

[egonrian]

text-bison@001 has been discontinued since Saturday

Computation based evaluations are only available for text-bison@001. So the only option available is to discontinue the computation based evaluation folder.

Changes:

• Included the alternative link in the README.md file
• Renamed the folder for more clarity
• Included "DISCONTINUED" in every notebook in the folder
• Included an empty DISCONTINUED_FOLDER file in the folder

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[RajeshThallam]

@egonrian Can you please add a message on README and recommend to migrate to Gemini models.

These are the PaLM models that will be available until the new extended date of October 9, 2024:
chat-bison@001
text-bison@001
code-bison@001
codechat-bison@001
code-gecko@001

We strongly encourage you to migrate to Gemini 1.5 Flash and Gemini 1.5 Pro for improved performance. Please review our full guide on how to [migrate from PaLM API to Gemini API in Vertex AI](https://cloud.google.com/vertex-ai/generative-ai/docs/migrate/migrate-palm-to-gemini).