Creates base PaymentsApp

* Adds ability to add payments to a customer.
* Creates base form view for adding a payment to a customer inside the
  CustomersApp.Show.Controller
* Adds actionsRegion to CustomersApp.Show.Layout
* Closes actionsRegion and refreshes view after creating/canceling new
  payment. This allows for new (if applicable) element to draw itself in
  the transactions list.