Create a preview docs github action on pull request

[AdithyaSireesh]

Currently, we only see if the documentation builds correctly after merging changes into main.
Best practice is to have a separate workflow that builds and deploys the Sphinx documentation to a preview branch for each pull request. This allows reviewers to:

• See the rendered documentation as part of the regular PR review process

• Catch documentation build/import errors before merging

• Ensure that the documentation is always up-to-date and accurate

Proposal:
Create a workflow that, on each pull request, builds the docs and deploys them to a dedicated preview branch (e.g., gh-pages-preview), ideally in a subfolder named after the PR (e.g., pr-123).
This will make it easy for reviewers to preview and verify documentation changes before they are merged.