Balance admin

- admin can grant promotions to projects
- admin can see project's balances in the project overview
- admin can view the transaction history of each project
- rename payment history into transaction history
The last part is just appending a ')'. here is another example for how the templating language concatenates: https://github.com/openstack/horizon/blob/master/openstack_dashboard/dashboards/project/volumes/templates/volumes/volumes/detail.html