Improve security of website by changing/adding HTTP headers returned by server

Project:Web
Component:Main
Category:feature request
Priority:critical
Assigned:Unassigned
Status:active
Description

See: https://securityheaders.io/?q=https%3A%2F%2Ftrisquel.info&followRedirects=on

This issue wasn't reported by me, studio found it (https://listas.trisquel.info/pipermail/trisquel-users/2018-January/085580.html).