Add comprehensive documentation for implementing Revolut payments including backend controller, Vue component, Blade template, and JavaScript setup. The guide covers installation, configuration, and usage examples for both frontend and backend implementations.

- Improved exception handling in URequest class to return structured error responses for specific HTTP status codes (422, 400, 404).
- Added additional logging for debugging purposes.

- Introduced ShouldEmbedForm interface to define methods for handling built-in form attributes, validating checkout payloads, and hydrating checkout payloads.
- This interface aims to standardize the implementation of payment forms across different payment gateways.

- Added a static property to indicate if the service has a built-in form.
- Introduced a method to check for built-in form support and contract implementation.
- Enhanced the checkout method to validate and process payloads when a built-in form is available.

- Implemented a new checkout method in the Payable class to validate and process payment payloads.
- The method merges the payload schema, removes exceptional entries, and creates a payment record before proceeding with the checkout process.

…and order management

- Implemented ShouldEmbedForm interface in RevolutService to support built-in form attributes.
- Added methods for validating and hydrating checkout payloads.
- Refactored order creation and retrieval methods for better clarity and functionality.
- Improved error handling in cancel and refund methods, ensuring proper response structure.
- Updated createWidgetOrder method to streamline order processing and response generation.