bug#47823: Hardenize Guix website TLS/DNS

[bo0od]

Hi There,

Scanning Guix website gave many missing security features which modern 
security needs them to be available:

* TLS and DNS:

looking at:

https://www.hardenize.com/report/guix.gnu.org/1618568751

https://www.ssllabs.com/ssltest/analyze.html?d=guix.gnu.org

- DNS: DNSSEC support missing (important)
- TLS 1.0 , 1.1 considered deprecated since 2020
- Allow TLS 1.3 as it helps with ESNI whenever its ready by openssl
- Use only secure ciphers, disable old ciphers
- Force redirection of insecure connection with plain text to TLS
- HSTS/HSTS-preload support missing (important)


* Web Application (Headers):

I think its self explanatory:

https://securityheaders.com/?q=https%3A%2F%2Fguix.gnu.org%2F&followRedirects=on

ThX!