Export user loans list to excel or csv

Purpose: Users need to be able to export loans in CSV format in order to do more complex sorting and filtering, or to show a patron a list of their loans.

Split into UXPROD-1118 to handle fields with strikethrough below.

1. Scenario
   • Given the open loan screen
   • When a patron has at least one open loan
   • Display and activate the export function
2. Scenario
   • Given a patron with open loans
   • When a user clicks export on the open loans screen
   • Then the following fields, populated as they are on the Loan details page, are exported as CSV for each loan:
     • Borrower
     • Proxy borrower
     • Title
     • Contributors
     • Barcode
     • Call number
     • Location
     • Item status
     • Due date
     • Return date
     • Renewal count
     • Claim returned
     • Check in location
     • Loan policy
     • Loan date
     • Fee/fine
     • Requests
     • Lost
3. Scenario
   • Given a patron with non-anonymized closed loans
   • When a user clicks export on the closed loans screen
   • Then the following fields, populated as they are on the Loan details page for each loan, are exported as CSV for each loan:
     • • Borrower-
     • Proxy borrower
     • Title
     • Contributors
     • Barcode
     • Call number
     • Location
     • Item status
     • Due date
     • Return date
     • Renewal count
     • Claim returned
     • Check in location
     • Loan policy
     • Loan date
     • Fee/fine
     • Requests
     • Lost