Badger implementation isn't tested and works not well,
but requires human resources to maintain.
Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>
Make it store its internal `zap.Logger`'s level. Also, make all the
components to accept internal `logger.Logger` instead of `zap.Logger`; it
will simplify future refactor.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
