allow auto detect user lang without setting it or login

Problem to solve

1. login user need to go to setting panel set site ui lang
2. not yet login user, can't change site ui lang

Intended users

1. people who is not english user

Further details

Proposal

1. auto detect browser info and choose lang
2. allow ghost can change site lang

Permissions and Security

Documentation

Testing

What does success look like, and how can we measure that?

Links / references