Update po_translatable_pages for Tails 3.0

Originally created by @sajolida on #11573 (Redmine)

On each release n of Tails 3.0, 4.0, etc. po_translatable_pages should be
updated to disable translations of news/version_*, news/test_*, and
security/Numerous_security_holes_in_* for release n-2.

Also create a ticket for Tails 4.0.

Feature Branch: feature/11573-update-po_translatable_pages-for-master