feat: integrated whatsapp features

[SOUVIK-D10]

Issue Link

Closes #27

Changes Made

• Added WhatsApp module with
  ->A generic interface WhatsappService
  -> it's abstract WhatsServiceImpl that contains the pre-implemented code for sending notifications
  -> WhatsappOrderNotification Interface and its Impl for handling the payload creation part (this is the part that is to be modified and adjusted for specific needs of template)
• Refactored Order service and it's impl : Changed return type of cancleOrder to OrderResponse for easier WhatsApp integration
• Refactored Order Controller : integrated WhatsappOrderNotificationService in update, create and cancel methods

More Details on WhatsApp features(important)

1. Meta has strict policies on templates and messaging so it is recommended to create templates and app with proper business registrations. More over the test apps with unverified business may not send messages from the given test number.
2. The WhatsApp Order Notifications are designed to be Asynchronous in nature so they should be able to handle multiple requests. So even if WhatsApp is down or Meta rises any policy issue the backend still processes the request

Type of Change

• [ Y ] New feature :- WhatsApp Module
• [ X ] Bug fix
• [ X ] Documentation update
• [ Y ] Code refactor :- Integrated WhatsApp Module with OrderController

Backend Testing

• [Y] API endpoints tested locally with Postman/curl

Functionality

• Any Order NON GET interaction automatically triggers whatsapp notification with customer's phone number

Additional Notes

• Unverified business cannot send messages from test app and can only mock them
• Adding better more whatsapp services like support and all.

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Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 6 comments.

[SOUVIK-D10]

Implemented suggested changes
Handled customer name and phone number issues directly in controller saving the calls to whatsapp service