Update heading in Item detailed view. Implement linking to associated instance and holdings

Purpose: Update the second heading pane in the Item record detailed view to include links to the associated Instance and Holdings.

Stories:

1. Story
   • Login to FOLIO Snapshot as user diku_admin, go to Inventory
   • Search for any instance, with associated holdings and item
   • When viewing the Item record in detailed view, and the second top bar
   • Then the first line displays
     • Instance: [ instance title ][.][ space ][ Publisher][,][ Publication date]
     • The [ instance title ] is displayed as a hotlink to the detailed view of the given instance record
2. Story
   • When viewing the second top bar
   • Then the second line displays
     • Holdings: [ Holdings effective location ][ space ][>][ space ][ Holdings call number ]
     • The [ Holdings effective location ][ space ][>][ space ][ Holdings call number] is displayed as a hotlink
3. Story
   • When clicking the [ instance title ] hotlink
   • Then the given instance record is displayed in the regular detailed view (3rd pane view).
4. Story
   • When clicking the [ Holdings effective location ][ space ][>][ space ][ Holdings call number ] hotlink
   • Then the given holdings record is displayed in the regular detailed view (full view)