docs: add french README

[eze-kiel]

What is it?

• [ ] Bugfix (user facing)
• [x] Feature (user facing) -> doc improvement
• [ ] Codebase improvement (dev facing)
• [ ] Meta improvement to the project (dev facing)

Description of the changes in your PR

This PR adds the full french README (doc/README.fr.md, and adds its link in README.md at the root of the repo.

Before/After Screenshots/Screen Record

• Before:
• After:

See screenshot

Fixes the following issue(s)

No code fixes.

APK testing

No need as the code is not impacted by this PR.

Due diligence

• [x] I read the contribution guidelines.

[eze-kiel]

Nice catches! I'm fixing them right now

[eze-kiel]

hi @BrightDV, thanks for your review! it should be good this time :)

[BrightDV]

Can someone merge this, please?

[TobiGr]

Thank you for your work. Your changes were merged in #10240