Point Tails 2.x users to the Tails 3.0 full upgrade
Originally created by @intrigeri on #12497 (Redmine)
… despite the architecture (i386 vs. amd64) mismatch. In other words, have i386 UDFs for 2.x point to the full upgrade to 3.0.
This must be done during the 3.0 release process.
Feature Branch: web/release-3.0