Refactor set_route_... and other action methods

[0xjac]

There is some copy/paste on those set_route_... and other action methods (L334-L366).

Use a helper method instead:

class eSSP(object):

    def _action_helper(self, amount, currency, prefix, action):
        self.actions += action
        self.actions_args['{}_amount'.format(prefix)] = amount * 100
        self.actions_args['{}_currency'.format(prefix)] = currency.upper().encode()
        
    def set_route_cashbox(self, amount, currency="CHF"):
        """Set the bills <amount> in the cashbox
           NV11: Set the bills <= amount in the cashbox"""
        self._action_helper(amount, currency, 'routec', 'c')