Add Support for Webhook Handling and Validation

[karaOdin]

Currently, the Go package for our payment gateway is missing support for handling incoming webhook requests and validating those requests. This is an essential feature for users who need to securely process events triggered by our payment gateway.

Expected Functionality:
Webhook Handling:

-   Implement a function to receive incoming HTTP POST requests containing the webhook payload.
-   Support parsing the payload and extracting necessary fields for further processing.

Request Validation:

-    Include methods for verifying the authenticity of the webhook requests, such as checking for a signature header or validating the payload against a secret key.
-    The validation should ensure that only legitimate requests are processed.

References:

• How to handle Chargily Pay webhooks https://dev.chargily.com/pay-v2/webhooks

[BigBr41n]

as soon as possible , currently i'm refactoring the package to be more scalable and focusing on clarity and ease of use.
support for Webhooks and validation will be added soon