Stripe Node SDK v22: breaking API changes

This release contains several breaking changes to types and method call handling.

• Stripe.StripeContext is no longer exported as a type
• Stripe.errors.StripeError is no longer a type
• CJS entry point no longer exports .default or .Stripe as separate properties
• The Stripe import is now a true ES6 class; calling Stripe("sk_test_...") without new no longer works
• stripeMethod has been removed
• Callback support for API methods has been removed
• Passing a plain API key as a function argument no longer works
• Keys from params and options objects are no longer mixed; RequestParams must come first and RequestOptions second
• Removed methods from StripeResource: createFullPath, createResourcePathWithSymbols, extend, method, and _joinUrlParts
• Calls like stripe.customers.retrieve('cus_123', 'sk_test_123'), passing an API key inside params, or passing a callback function no longer work

Update code and types to match the new v22 conventions.

• Use new Stripe() to construct a client instead of calling Stripe() directly
• Replace Stripe.StripeContext with Stripe.StripeContextType
• Replace Stripe.errors.StripeError type usage with typeof Stripe.errors.StripeError or Stripe.ErrorType
• Replace callback-based API calls with async/await
• Move any per-request API key into RequestOptions.apiKey instead of passing it as a function arg
• Ensure RequestParams is always the first argument and RequestOptions the second, passing undefined explicitly if only options are needed
• Remove any use of the removed StripeResource methods
• Consult Stripe's published migration guide for v22 for full details