Add security headers on Amplify distribution

[xavierraffin]

Amplify framework recently release a new feature that allow the user to inject some static headers from a Amplify hosted environment: https://docs.aws.amazon.com/amplify/latest/userguide/custom-headers.html

It will be nice to create such a file to inject HTTP headers where possible. Here is a reference of possible headers to inject: https://owasp.org/www-project-secure-headers/

Please add a small documentation section with this PR (maybe in the feature list, the dev doc and/or the user doc)