UX: Hierarchical level navigation bar. Instance display.

Purpose: For the Inventory app, library staff want to see instance > holdings > item data as the out put of a given search wether the search is in the Instance, Holdings, or Item segment.
When searching the instance segment, and viewing the 3rd pane, then a level navigation bar is displayed right under the top heading, and a short description of the instance record. The full view of the instance record is displayed when clicking the expansion icon. With this change we get consistent UX for all three record types instance, holdings, and item.

Search for an instance record:

Search for a holdings record

Search for an item record

A couple of outstanding UX/UI issues, which we'd need to find a solution for:

1. sorting of the results in the result list, e.g. by Index title, the publication date, etc.
2. the functionality of the navigation bar, in the top of the third pane, and what data to display

Holdings	Item

More details: See UX live demo: https://ux.folio.org/prototype/en/inventory

Link to the UI working groups wiki-page: https://wiki.folio.org/pages/viewpage.action?pageId=62555575