Instance - language filter/facet

Purpose:
This UI implementation of the Language filter covered by MSEARCH-4

User story statement(s):
As a librarian searching inventory
I want to see what publication languages are present
so that I can limit my search results to a desired language

Scenarios:

1. Scenario:
   • Given the Inventory-es app
   • When the landing page opens
   • Then the language filter displayed in the left pane in Instances tab and the filter is collapsed
     
2. Scenario:
   • Given the language filter is expanded
   • When the user starts typing in the filter's textbox
   • Then autocomplete suggests available languages
3. Scenario:
   • Given the user typed the language in the filter's textbox
   • When the language is selected
   • Then search results are populated with the instances fulfilling the searched language
4. Scenario:
   • Given the Inventory-es app
   • When the results pane is populated
   • Then the language filter is expanded and shows checkboxes with languages that meet the search criteria followed by the number of instances for each language. The languages are ordered by number of hits in descending order:
     
     Note: The mockup displays incorrect order of the languages
5. Scenario:
   • Given the checkbox in the language filter/facet
   • When the user selects a checkbox
   • Then the results list contains only the records that are published in this language
6. Scenario:
   • Given the checkbox in the language filter/facet
   • When the user selects more than one checkbox
   • Then the results list contains instances that were published in either of selected languages (logical disjunction)

Out of scope:

1. Entering same search in search box and selecting filter
2. Showing only top 5 options with by "More..." link