Grow /home on rsync.lizard

Originally created by @intrigeri on #17385 (Redmine)

Once tails/tails#15287 is done, at some point in our release process, rsync.lizard:/home will need to store all the IUKs to the version to be released.
The number of such IUKs and the corresponding disk space will grow over time during the 4.x cycle, then go down to 0 when 5.0 is released, then grow over time during the 5.x cycle, etc.
Let’s be prepared for the worst case scenario ASAP, so this does not end up blocking a release :)

Related issues

• Related to tails/tails#15287
• Related to tails/tails#17412