Improve the Mozilla Observatory score

[Natim]

https://observatory.mozilla.org/analyze.html?host=www.kinto-storage.org

[Natim]

I initiated a discussion with Netlify support about that.

[Natim]

Answer from netlify:

Fortunately you can already set custom headers:

https://www.netlify.com/docs/headers-and-basic-auth/

Do be careful to read about what the headers you'll set might do before applying those generic suggestions from mozilla, though - the headers don't just get you a better score, they also can change the behavior of your site.

[Natim]

I have implemented most of the recommanded header going from D+ to B grade, if someone wants to work on the CSP header, feel free to help :)