Bug 11573: Make rental accountlines translatable

Bug 11573: Make rental accountlines translatable

To test:

1. Set up an item type with a rental charge
2. Issue an item with that item type
3. Check fines, a charge of type 'Rent' will be visible with a
description of 'Rental'.
4. Renew the item
5. Check fines, a charge of type 'Rent' will be visible with a
description of 'Renewal of Rental Item TITLE BARCODE' where TITLE and
BARCODE are the items title and barcode.
5. Apply the patch
6. Repeat steps 1-4, charge descriptions should now be empty and charge
types should display 'Rental fee' and 'Renewal of rental item'.
7. Repeat steps 1-6 for an item type with a daily rental charge and note
the charge types are now 'Daily rental fee' and 'Renewal of daily rental
item'

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>