Bug 28720: Update the process of adding a checkout note in the OPAC

Bug 28720: Update the process of adding a checkout note in the OPAC

This patch moves the entry of checkout notes into a modal window with
the goal of making note entry easier.

To test, apply the patch and make sure the AllowCheckoutNotes system
preference is enabled.

- Log in to the OPAC as a user with checkouts.
- On the "Your summary" page, confirm that the table listing your
  checkouts has a "Report a problem" column with "Add note" buttons.
- Click an "Add note" button. A modal window should be shown which
  includes the title of the item, a textarea for writing a note, and a
  hint, "Your note will be shown to the librarian when the item is
  checked in."
- Add a note and submit it.
- The modal should close and a note at the top of the page should tell
  you your note has been saved. The contents of your note should be
  shown below that along with an "Edit note" link.
  - Confirm that the "Edit note" link works as expected.
  - Confirm that the "Add note" button you clicked in the table of
    checkouts now reads "Edit note."
    - You should be able to click this button and edit your note.
- Confirm that each note button works to add a note to the correct
  title.
- Confirm that the "Renew selected" and "Renew all" controls work.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>