Test Matrix in Tails

Originally created by @piratepartyaustria on #15209 (Redmine)

Thunderbird 102 supports Matrix
See https://matrix.org/docs/projects/client/riot.html
The revolt client is in Debian Buster and newer.

Blueprint: https://gitlab.tails.boum.org/tails/blueprints/-/wikis/mobile_messaging/

Parent Task: #14567

Edited May 13, 2022 by intrigeri

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