Make sure users / translators know that they are visiting the staging wiki when they do
Originally created by @Anonymous on #15649 (Redmine)
We should make sure that users are aware that they are not visiting tails.boum.org but the staging wiki when they do. Using a banner, a background color or similar.
Parent Task: #15080
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information