Add system test for creating a recurrent edition
We have had bugs related to creating a descendent edition of a recurrent edition (e.g. #675 (closed)), including UI bugs. This feature is only used a few times per year, so bugs often take a while to be discovered.
We should add system tests which copy a complex recurrent edition (with projects, tags, etc.) by clicking the "create new edition" button under "visibility and dates" on the recurrent edition to create a descendent edition, then only changes the name, and clicks the creation button. Then it should verify that all elements (e.g. tags, projects, project tags, roles, project roles, etc.) are copied.