fix some failings and refactor code

hyrax/app/assets/javascripts/bulkrax/importer.js.erb

hyrax/app/controllers/bulkrax/importers_controller.rb

hyrax/app/jobs/import_s3_url_job.rb

hyrax/app/models/bulkrax/file_factory.rb

hyrax/app/models/bulkrax/importer.rb

hyrax/app/models/bulkrax/rub_csv_entry.rb

hyrax/app/parsers/bulkrax/rub_csv_parser.rb

hyrax/app/views/bulkrax/importers/_rub_csv_fields.html.erb

hyrax/app/views/bulkrax/importers/index.html.erb

hyrax/app/views/bulkrax/importers/show.html.erb