Review the Weblate-based infrastructure that updates and pushes PO files

Originally created by @intrigeri on #16326 (Redmine)

… so we are confident that PO changes pushed and checked via sysadmin#15402 (closed) have gone through the expected process.

Edited May 15, 2020 by intrigeri

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