.fixture loads a bunch of rows as an rspec macro.
Review feedback.
Drop `Askari::Schema::Application` for `Askari::Schema`.

This doesn't pretend to be an `Application`, it just offers a
version-independent facade.
Drop an unused method.
Rename blockcache, blocksize and bloomfilter by adding underscores.
Knock out a TODO.
Drop another TODO.
Drop `splits_file` from schema to avoid handling paths.

We'll take care of it in options to `Creator`.
The creator tool can now specify splits files.