Make charabia default feature optional

[vincent-herlemont]

Pull Request

What does this PR do?

Fixes #627

Thank you so much for contributing to Meilisearch!

[ManyTheFish]

Hello @vincent-herlemont, is it possible to make it more granular in order to allow choosing which language is supported?

Thanks!

[vincent-herlemont]

@ManyTheFish Sure commit here: https://github.com/meilisearch/milli/pull/632/commits/8cd5200f48b5be9629cc7107aebdcc06bcf27d73

[bors[bot]]

Build succeeded:

• Run Rustfmt
• Tests on macos-latest
• Tests on ubuntu-20.04
• Tests on windows-latest