Additional features requested for payment group info

For the recent push concerning:

there seems to be perhaps some additional things needed:

  1. an initial filter on payment groups should probably be added: ‘completed:false’
  2. it would be nice to have a tree view instead of a flat view which necessitates double clicking on each entry to find the date(s) of the payments in the group … which should then be grouped by date. (NB: the sepa_group_payment_id could/should be shown here as well)
  3. it seems impossible to order descending by number, the ordering is done by text which is somewhat annoying (this is already reported here:Issue 9344: sorting payment groups by number needs to sort numerically - Tryton issue tracker)