contributor management: increase space efficiency
contributor management: increase space efficiency

fixes #763

noplanman/podlove-publisher,katrinleinweber/podlove-publisher,podlove/podlove-publisher,podlove/podlove-publisher,noplanman/podlove-publisher,noplanman/podlove-publisher,podlove/podlove-publisher,podlove/podlove-publisher,noplanman/podlove-publisher,katrinleinweber/podlove-publisher,noplanman/podlove-publisher,podlove/podlove-publisher,podlove/podlove-publisher,katrinleinweber/podlove-publisher,katrinleinweber/podlove-publisher,katrinleinweber/podlove-publisher