Give - Stripe Gateway 2.6.0

* Important: This update requires Give 2.5.0+ and the latest versions of add-ons to work properly. Please perform a site backup and ensure you have activated your license keys to ensure your add-ons update properly before updating.
* New: Added support for Stripe in Give Core.
* New: Added a settings section to provide information about the Stripe webhook status.
* New: The "Company Name" field, if used, is now sent to Stripe as meta information.
* New: The Stripe API version has been updated to `2019-05-16`. Please test your integrations accordingly.
* New: The add-on now uses the "Payment Intents" feature for all donation processing. This is to ensure that we are using the recommend API from Stripe and paves the way for 3DS and Stripe Checkout version 2.0 in the near future.
* Fix: An AJAX response error response error would occur in certain configurations when multiple donation forms are on the same page.

* Fix: Resolved a missing condition with billing details affecting Stripe ACH payments from properly validating whether billing details were required or not.

* Fix: When the Stripe add-on is activated the requirements for the billing details were removed from donation forms. This allowed donors to process donations without inputing their address. Many organizations require the address as required to donate and this resolves the issue with the fields being non-required.