Add benefactors registration form and address autocomplete

Ghost User
2019-05-15T20:42:03+02:00

Closes #560

### Short description

Add benefactors registration form

### Steps to use this feature

1. Go to the 'become a member' page
2. go to the benefactor form
3. Enter your data (note the autocomplete) and follow the steps.

The documentation for the registrations packages outlines all the possible steps.