Valid https certificates at LinuxTV.org

Hi all,

Today, I changed the https certificates at linuxtv.org to use valid certificates provided by Let's Encrypt (http://letsencrypt.org/).

I also changed the URLs to use relative links on most places (I didn't touch the legacy documentation), and the pointers to
https://patchwork.linuxtv.org and the links from patchwork and git to
https://linuxtv.org.

So, while the site keeps accepting http URLs as before, the default and recommended way is to use https everywhere.

I hope this will help the efforts to make the Internet safer ;)

Enjoy!

Regards,
Mauro