Bug 7651: Add a new permission for managing currencies and exchange rates

Bug 7651: Add a new permission for managing currencies and exchange rates

At the moment staff users need parameters or parameters_remaining_permissions
in order to be able to change exchange rates for acquisition orders.

This patch adds a new separate permission currencies_manage and
updates staff users currently having those permissions to get the
new permission as well.

To test:
- Create some staff users with different permission sets
  1) superlibrarian
  2) parameters
  3) parameters_remaining_permissions
  4) manage_circ_rules, but not parmeters_remaining_permissions
  5) all acquisition permissions
- Apply patch and run database update
- Verify new permission has been added and staff users updated
  1) remains the same
  2) + 3) will have currencies_manage
  4) remains unchanged, doesn't have new permission
  5) remains the same, will have access now because of having
     the top level acquisition permission
- Verify the changed pages work correctly:
  - navigation on admin home page
    NOTE: the acquisition parameters section will now honor all
    different related permissions (edi_manage, budget_manage,...)
  - navigation on acquisition home page
  - try to access currencies page directly

Signed-off-by: Charles Farmer <charles.farmer@inLibro.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>