chore: add new performance-oriented docs

[filipsobol]

PR based on #6628

[github-actions]

💙 vsf-next-demo successfully deployed at

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✅ filipsobol
❌ piotr-grzywa
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[filrak]

Overally, a great piece of content and I am super happy we are having it. Left some minor comments

[filrak]

Suggested change

	By default, when user enters your website, browser needs to create new connection for every resource request (JS, CSS, images etc). This requires performing three-way handshake every time.
	By default, when user enters your website, browser needs to create new connection for every resource request (JS, CSS, images etc). This requires performing three-way handshake every time that makes the responses slower.

[PiotrGrzywa]

This one is not up to date, content was changed.