fixes #638 : voting round seeds now open in a new tab
fixes #639 : ExternalTopicCollection is now created with active=False, i.e. in an unpublished state
fixes #637 : dashboard "Zdroje, které spravujete" no longer shows sources with "Archivováno bez smlouvy"
fixes #640 : when Source is assigned to a contract, its state is changed to "Archivován"
fixes #607 : the Harvest HTML datetime-local input should now be pre-filled with the selected date when creating a new Harvest
fixes #645 : default = date.today for TopicCollection.date_from
fixes #641 : when selecting an External TC in the Internal TC add form, auto-fill ETC's CS & EN title
RE #611 & #604 : Harvest form is now more dynamic – changing the harvest type triggers property changes & section hiding/showing. Will mark as closed when it's tested and agreed upon.
RE #636 : answered in issue, someone else should close it or assign next steps
active=False, i.e. in an unpublished state