feat(stripe): Add proper stringification via StripeAccount.to_str
feat(stripe): Add proper stringification via StripeAccount.to_str

Better stringification for Stripe accounts, using the 'business_name'
key in extra_data. Addresses #1871.

bittner/django-allauth,pennersr/django-allauth,rsalmaso/django-allauth,pztrick/django-allauth,pennersr/django-allauth,rsalmaso/django-allauth,pztrick/django-allauth,pztrick/django-allauth,AltSchool/django-allauth,AltSchool/django-allauth,lukeburden/django-allauth,AltSchool/django-allauth,bittner/django-allauth,lukeburden/django-allauth,pennersr/django-allauth,bittner/django-allauth,rsalmaso/django-allauth,lukeburden/django-allauth