csv importer should spawn ingest jobs for each work

[rococodogs]

right now ingesting is performed in a single job. if we enqueue a job for each work (after parsing metadata), we could leverage sidekiq's ability to run concurrent jobs

module Spot
  class IngestWorkJob < ::ApplicationJob
    def perform(work_type:, attributes:, depositing_user:)
      work = work_type.constantize.new
      env = Hyrax::Actors::Environment.new(work, Ability.new(depositing_user), attributes)
      Hyrax::CurationConcern.actor.create(env)
    end
  end
end

Spot::IngestWorkJob.perform_later(work_type: 'Image',
                                  attributes: { title: ['A Cool Work'] ... },
                                  depositing_user: User.find_by_username('DeposiBot'))