DEICH-6467 show correct shelfmark for all items

With Koha we got shelfmark (hyllesignatur) along with other informations about items, but Cicero does not have a concept of shelfmark, and thus not provided with holdings information.

Instead we have to fetch this information from the publication metdata stored in RDF. This commit adds a new endpoint to euler which takes a list of recordIds and returns all location components needed for constructing a shelfmark. This endpoint is called and the data merged with holdings information when fetching holdings from Cicero.