tor-tsocks-mua.conf left over from Claws Mail removal

Originally created by @intrigeri on #10904 (Redmine)

It seems that config/chroot_local-includes/etc/tor/tor-tsocks-mua.conf is present, and referenced in two design docs, while it is not used anymore. Please clean this up :)

Feature Branch: 451f:tails/feature/10737+icedove_design_doc

Parent Task: #10167 (closed)

Edited May 15, 2020 by intrigeri

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