Add a PaymentIntent.create classmethod?

[therefromhere]

Suggested by @Skorpyon in #938

...is it possible add class method to PaymentIntent same as it exist for Customer to create new intents?

payment_intent = PaymentIntent.create(customer=customer, amount=1000, currency='eur', **kwargs)

[therefromhere]

A PaymentIntent.create() classmethod is possible, though it seems like it would be a very thin wrapper around stripe.PaymentIntent.create (maybe just do a cls.sync_from_stripe_data on the result).

I was initiallly thinking maybe it should be a method of Customer instead, but since you can create PaymentIntents without a customer I think a PaymentIntent classmethod would be the way to go.

[nickdjones]

My PR should cover this https://github.com/dj-stripe/dj-stripe/pull/950

[therefromhere]

Removing this from 2.1.0 milestone because I don't think it's a blocker on release.

[therefromhere]

This might get bumped to 2.2