Update instructions for Next.js support with SSR

[paolodamico]

This tutorial is very outdated https://keajs.org/docs/intro/installation/nextjs, would be great to get an update on best practices when using Kea on a Next.js project with SSR enabled.

[mariusandra]

Hey @paolodamico , would it be better to remove that page? I'm not really a next user, so it's hard to keep that page up to date.

[paolodamico]

I think ideally it'd be great to update the tutorial so Kea can run properly on Next.js (I've been to a few hackathons recently and a surprising amount of hackers prefer Next.js over vanilla React), but if you don't have the bandwidth (which is totally understandable) I'd definitely recommend removing this page now to avoid confusion (maybe just keep a small note somewhere in the docs)