Bug 12646: Display all invoices on the same page

Bug 12646: Display all invoices on the same page

Only first 20 invoices were displayed on the page. Without pagination, DT
did not allow to show others.
This page explicitely removes the pagination option in order to display
all invoices on the page.

Test plan:
1/ Create 21+ invoices
2/ Go on acqui/invoices
3/ Verify all invoices are displayed.

Signed-off-by: Paola Rossi <paola.rossi@cineca.it>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>