Add API for webhooks following stripe's API. Keep existing /_config/webhooks
for registering webhooks with predefined secrets.

When localstripe is injected into the page, it may not be the last script
element. Find a script that matches a domain followed by js.stripe.com/v3

Also allow starting with '//', 'http://' or 'https://'

Give extra data to Bad Request errors to explain which parameter is missing
or invalid.

Allow Stripe to be instantiated with the 'new' operator.

canMakePayment resolves null to indicate no support for any paymentRequest.

Support creating Elements of types: card, cardNumber, cardExpiry, cardCvc.

Add off() to remove event listener

Add extra methods for Element: blur, focus, clear, update.
Trigger extra events: ready, blur, focus.

Pass event object to listeners for change event

Filter customers by email if param is present

Add created, succeeded, payment_failed, canceled webhooks for payment_intent

Add payment_method.attached, payment_method.detached webhook events

Calls confirmCardPayment() with option handleNextAction: false

Payment flow may be at confirmation step

At debug level, log when sending a webhook.

Move dockerfile from README to its own Dockerfile

Allow specifying a standard and stripe connect webhook through env vars:

WEBHOOK_URL
WEBHOOK_SIGNING_SECRET
CONNECT_WEBHOOK_URL
CONNECT_WEBHOOK_SIGNING_SECRET

Or through vault using AWS IAM authentication, needing these env vars:

VAULT_ADDR
VAULT_ROLE
ENVIRONMENT

will look at `secret/fatsoma/${ENVIRONMENT}/api/payment` for keys:

stripe_webhook_url
stripe_webhook_signing_secret
stripe_connect_webhook_url
stripe_connect_webhook_signing_secret

Allow health check to use /_status without auth

Prevent memory growth by deleting PaymentIntent after we have finished using it.

Disable disk loading and saving

https://www.pivotaltracker.com/story/show/182539313

Update to aws ecr get-login-password