Specify USD currency in the Customers Portal

Feature Request

Problem

$ (Dollars) is widely use in different countries and from what we're using in the customer portal, sometime it can give the impression that the customer is being charged in their local currency. Especially when Tax is included in the calculation.

Proposal

We should clearly display that we're charging them in USD, as we do in the renewal reminder emails.

Places to update currency:

Page	Screenshot
Subscription display
Purchase flows

Next steps (if any)

How will we measure success?