Removes acid-state specific code and the former BlogDB module, in its
stead the new BlogStorage module contains stubs for the functions that
will be filled in with DNS-based storage.
This code is unformatted and will not currently serve a working blog.
This updates some old code that makes assumptions via pattern matching
to instead make assumptions via a Prelude function.
This is known to be safe as it has been running fine for almost a
decade now, but the recent MonadFail changes broke the build.
