📃 Add documentation for gradio inference

[ashwinvaidya17]

Description

• Add documentation for Gradio inference.

• Fixes Add Gradio Documentation #341

Checklist

• My code follows the pre-commit style and check guidelines of this project.
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes

[samet-akcay]

Have you checked whether Gradio works fine? When I checked it on Friday, it was partially working.

[ashwinvaidya17]

Have you checked whether Gradio works fine? When I checked it on Friday, it was partially working.

Yeah openvino was not working but I've changed that line in the file. I've tested both the examples on my windows machine.

[samet-akcay]

Maybe another PR, but I think we should use the lightning inference to handle the meta-data automatically. Otherwise, we manually need to tune the threshold on the UI

[ashwinvaidya17]

I think this requires refactor but we should load the initial value of threshold from the model/metadata json file. With that as the default value, the users can then play around with the threshold.