Stop using the fallback blacklist, and delete it
We require relay operators to opt-in to being fallbacks, and we won't ever switch to opt-out. (See legacy/trac#24789 (moved).)
So we don't need the fallback blacklist any more.
We should stop loading the blacklist in the script, then delete it.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information