Autodetect user language

[rluders]

Description

It would be pretty nice if we could detect the browser language or user IP. I don't know which one is the best, and preselect the website language based on this information.

UI Resource

N/A

Aditional information

Maybe we can find some information here: https://v2.docusaurus.io/docs/i18n/introduction

Possible unknowns

• Should we use IP or Browser language?
• Does Docusaurus already support it?

[marianyfs]

In the Docusaurus documentation there is a topic on the subject:

- Automatic locale detection: opinionated, and best done on the server

Issue: facebook/docusaurus#4681