Add call number sorting to user's open loans and closed loans

Purpose: Allow user to sort loans by call number.

1. Scenario (sort open loans by call number ascending)
   • Given a user's open loans, sorted by a column other than call number
   • When the title of the column call number is clicked
   • Then sort user's open loans by item's shelving order, ascending
2. Scenario (sort open loans by call number descending)
   • Given a user's open loans, sorted by call number, ascending
   • When the title of the column call number is clicked
   • Then sort user's open loans by item's shelving order, descending
3. Scenario (sort closed loans by call number ascending)
   • Given a user's closed loans, sorted by a column other than call number
   • When the title of the column call number is clicked
   • Then sort user's closed loans by item's shelving order, ascending
4. Scenario (sort closed loans by call number descending)
   • Given a user's closed loans, sorted by call number, ascending
   • When the title of the column call number is clicked
   • Then sort user's closed loans by item's shelving order, descending