Bug 29309: Make 'Pay all fines' be 'Pay all charges'

Bug 29309: Make 'Pay all fines' be 'Pay all charges'

It is not just fines, it is also fees, etc.

To test:
1. Have a patron with debt
2. Go to the circulation page for the patron
=> FAIL: There's a button saying 'Pay all fines'
3. Apply this patch and reload page
=> SUCCESS: The button now says 'Pay all charges'
4. Enjoy the new terminology
5. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
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>