Add temperature model comparison example

[aman-coder03]

• Closes Add temperature model comparison example for ModelChain #2695
• I am familiar with the contributing guidelines
• Tests added
• Updates entries in docs/sphinx/source/reference for API changes.
• Adds description and name entries in the appropriate "what's new" file in docs/sphinx/source/whatsnew for all changes. Includes link to the GitHub Issue with :issue:`num` or this Pull Request with :pull:`num`. Includes contributor name and/or GitHub username (link with :ghuser:`user`).
• New code is fully documented. Includes numpydoc compliant docstrings, examples, and comments where necessary.
• Pull request is nearly complete and ready for detailed review.
• Maintainer: Appropriate GitHub Labels (including remote-data) and Milestone are assigned to the Pull Request and linked Issue.

This PR adds a new Sphinx-gallery example under docs/examples/iv-modeling that compares SAPM, Faiman, and PVsyst temperature models using identical environmental inputs

[AdamRJensen]

@aman-coder03 pvlib is developed by solar energy modelers and is a difficult project for general programmers to get involved with.

For a gallery example to be meaningful, the contributor needs to have insight into solar energy modeling (ideally some experience with using pvlib) for the example to be meaningful. While the gallery example you propose is technically correct, it does not go into the technical details behind the temperature models to discuss why they differ.

Unfortunately, our reviewer capacity is limited and we cannot accept PRs from people without solar experience.