Select default shipping and billing address for draft orders

[martijnvdbrug]

Is your feature request related to a problem? Please describe.
It's a bit annoying that you have to select a shipping and billing address when creating a draft order for existing customers, because they do have default addresses.

Describe the solution you'd like
It would be nice if a customer's default address is set on a draft order when I select an existing customer.

Describe alternatives you've considered
Doing it manually...