remove metabox around feed overview
remove metabox around feed overview

fixes #18

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