Can be used via `-auth.url=file://`. Only supports bcrypt password
hashes ($2y). Use e.g. `htpasswd -c -BC 14 <filename> <user>` to create
a file. Documentation forthcoming.
Not built by default, but can be added with `go build -tags nullauth`.
Enabled by running tokidoki with `-auth.url null://`. Very useful for
simpler debugging when you don't want manage test accounts with actual
passwords.
