Move docs to vitepress

[adarshmadrecha]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the feature has not already been requested

🚀 Feature Proposal

I am proposing that the docs be moved to VitePress.

Me and my colleagues can take this up. If required, can also create a mockup/sample page.

Motivation

The current docs does not have "Dark" Mode, which I feel is must have for any framework docs/website.
On each page naigation, entire page loads, hence the navigation does not feels instantaneous.

Example

No response

[climba03003]

I am transferring this issue to website.
We already have plenty of issue on using new framework for the website but it seems to me most of them is lack of developing after certain times.

See https://github.com/fastify/website-next
Refs fastify/website#322