/usr/share/doc/tails/website/torrents/rss.html is not reproducible

As show by https://jenkins.tails.boum.org/job/reproducibly_build_Tails_ISO_feature-5630-deterministic-builds/10/artifact/build-artifacts/diffoscope.html, the ordering of .torrent files in there can vary. I don’t think it’s relevant to ship this file in the ISO, so I suggest adding it to config/chroot_local-includes/usr/share/amnesia/build/mksquashfs-excludes.

Feature Branch: bugfix/12619-drop-rss.html

Original created by @intrigeri on 12619 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information