Bug 15004: Allow to change amounts of duplicated budgets

 Bug 15004: Allow to change amounts of duplicated budgets

When duplicating a budget we now have the possibility to change amounts
of budget and funds by a given percentage.  Additionally, we can
configure how to round the amounts.

Test plan:
1. Create a budget and several funds with different amounts
2. Duplicate it using the 2 new options
3. Check that the amounts are correct

Signed-off-by: Frederic Demians <f.demians@tamil.fr>
  It works exactly as advertised. Was happy to see that decimal point
  can be used: for example, increase a budget by 2.6%, and round the
  amound to 0.5.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>