Bug 23442: Add refund option to patron account page

Bug 23442: Add refund option to patron account page

This enhancement adds a refined workflow to allow librarians
to refund payments to patrons and record these refunds on the
patrons account.

The use case is that a patron has paid for something before
then performing an action that may require some level of refund
to be actioned.  Perhaps they are returning a lost and paid for
book.

Test plan:
1) Undertake a series of transactions that result in a debit
   accountline being partially or fully paid off.
2) Note that a new 'Issue refund' button appears next to a
   debit (but only if your user has the refund permission or
   is a superlibrarian)
3) Click the 'Issue refund' button and a modal should appear
   pre-populated with the amount - amountoutstanding.
4) You should be able to edit the amount you wish to refund,
   record the refund or cancel.
5) Signoff

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>