Springer numeric alphabetical (Basic research in cardiology)

This Springer style uses numeric labels for the references, orders them alphabetical and does not use "et al." It is a simple adaption of the style "springer-basic-brackets-no-et-al"
where I just added the sort keys. For the discussion in the forum see https://forums.zotero.org/discussion/39334

( I don't know why my former commit "deutsche-sprache" is appearing here as well, but I hope that is somehow solves out.)