Set a warning message in RCs and alpha releases
tl;dr: some users seem to have migrated to Tails 3.0~alpha1 for what seems to me like real usage, not for testing purposes.
spriver suggested that “we should have a custom background image for
alpha/testing releases which is saying blahablah this is dangerous”. We
could generate such an image at build time if the conditions are right,
e.g. we are building from a tag with
-rc in it.
Feature Branch: feature/12003-custom-home-for-rc+force-all-tests