1. Optimised the code and added helping docstring
2. Update the functionality as per payu documentation
3. Update the request/response structure
4. Simplyfy the payment initialization functionality.
5. Update the payment urls
6. Added the payment gateway codes

• Paytm payment gateway added
• Updated documents
• Created a new application for paywix integration with Django 3.1.6

Updated the Paywix with payu api services like follows:

1. getPaymentResponse
2. chkMerchantTxnStatus
3. refundPayment
4. getRefundDetails
5. getRefundDetailsByPayment

The PR updated with following functionalities

Remove all unwanted third party integrations
Remove unwanted imports
Remove Django independent functionalities
Make the Functionalities depends only Python not any specific framework

The PR updated with following functionalities

Remove all unwanted third party integrations
Remove unwanted imports
Remove Django independent functionalities
Make the Functionalities depends only Python not any specific framework