A MigrationDeepFinderInterface is a MigrationFinderInterface, which locates migrations not only in a directory itself, but in subdirectories of this directory, too.
MigrationFinderInterface implementations locate migrations (classes that extend
Doctrine\DBAL\Migrations\AbstractMigration) in a directory.
Schemaobjects to be passed to the migrations class.
Schemaobjects for the diff command. A schema provider should return the schema to which the database should be migrated.