Template Generation - Allow ability to choose address on generation screen

To avoid having multiple providers due to multiple office locations in Neos, we encourage the use of multi-addresses. However, merge templates typically pull from the Default Address. So if someone has to send something to the Billing department and not the default address, they have to either hand-type the letter or add a second provider for just the billing department.

If we were able to choose the address we wanted to use at time of template generation, it would avoid cluttering up our Neos with multiple provider cards for the same company.