Add microsoft/phi-2 for Text Generation

[jgyasu]

Pull Request description

Fix #90

microsoft/phi-2 is a small language model with just 2.7 billion parameters. Currently, Rago lacks small language models, which are helpful in use cases where there are resource-contraints and it is not possible to make API calls because of the privacy issues.

This PR adds phi-2 to Rago.

Pull Request checklists

This PR is a:

• bug-fix
• new feature
• maintenance

About this PR:

• it includes tests.
• pre-commit hooks were executed locally.
• this PR requires a project documentation update.

Author's checklist:

• I have reviewed the changes and it contains no misspelling.
• The code is well commented, especially in the parts that contain more
  complexity.

Reviewer's checklist

Copy and paste this template for your review's note:

## Reviewer's Checklist

- [ ] I managed to reproduce the problem locally from the `main` branch
- [ ] I managed to test the new changes locally
- [ ] I confirm that the issues mentioned were fixed/resolved .

[jgyasu]

@xmnlab I will appreciate a review :)

[xmnlab]

thanks @jgyasu ! appreciate it

[github-actions]

🎉 This PR is included in version 0.14.0 🎉

The release is available on:

• 0.14.0
• GitHub release

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