Description of problem: Since we are using boostrap , we should change the loan setting box from using jquery UI to boostrap modals.
This is already complete in the new-system-page branch, which is expected to become Beaker 0.18. The existing loan settings widget is replaced by a new Loan tab. https://beaker-project.org/dev/proposals/system-page-improvements.html#new-loan-tab
Duping this onto bug 1014438 since there is no reason to track it separately. *** This bug has been marked as a duplicate of bug 1014438 ***