Add hardware 2FA note to PayPal

Add a note to PayPal's section in _data\payments.yml, explaining that
hardware based two-factor authentication is no longer available. Fixes
#880.
Remove hardware support for PayPal

Explicitly state that hardware support for two-factor authentication
with PayPal is not available.
Merge pull request #885 from psgs/paypal-fix

Add hardware 2FA note to PayPal