add python Collect Performance Metrics demo

[mabeijing]

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Description

Motivation and Context

Types of changes

• [ ] Change to the site (I have double-checked the Netlify deployment, and my changes look good)
• [ ] Code example added (and I also added the example to all translated languages)
• [ ] Improved translation
• [ ] Added new translation (and I also added a notice to each document missing translation)

Checklist

• [ ] I have read the contributing document.
• [ ] I have used hugo to render the site/docs locally and I am sure it works.

[CLAassistant]

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[harsha509]

Hi @mabeijing ,

Hope you're doing great!

Did you get a chance to look into above comments ?

[diemol]

Added and given credit via https://github.com/SeleniumHQ/seleniumhq.github.io/commit/a5f4a07bc7ac854b4ee4a89af3cd7d23a628281b