[WIP] support to create return authorization and customer refund in netsuite

[aniket12chouhan]

1. Retrieves JSON files containing Return Authorization data from a specified directory on the SFTP server.
2. Transforms Sales Orders into Return Authorizations, sets return reasons, order status, and updates item quantities and amounts.
3. If Return Authorizations create successfully then Creates Item Receipts corresponding to each Return Authorization.
4. If Return Authorizations and Item Receipts created successfully then Generates Credit Memos from the Return Authorizations.
5. Create Customer Refunds based on Credit Memos, associating them with the respective customers and payment methods.
6. Added functionality to create directories in the SFTP location to facilitate efficient file transfers.
7. Implemented support for manual receipt of returned items in sales orders, triggering the creation of credit memos and customer refund records using a User Event Script.