Add seeds to existing seedlist

See NASC-71

Add seeds to existing seedlist (New Feature)

It would be nice if you could add and/or replace seeds in existing seedlists

Currently, some curators create new a seedlist and configuration every time a single seed is added. They use the "Add seeds " function on the page HarvestDefinition/Definitions-edit-selective-harvest.jsp instead of just modifying the seedlist itself: This results in a new seedlist and configuration causing a lot of noise and an excessive number of seedlists and configuration that is hard to manage.

Possible Design:

Choose existing seedlist

Choose new configuration ny konfiguration