[ADD] purchase: EDI with SPS commerce

[Felicious]

Provide information about how Odoo databases can integrate with the SPS Commerce connector in Odoo 16.

Key sections:

1. Briefly explain Electronic Data Interchange (EDI) and its role in automating data exchanges between companies.
2. Introduce SPS Commerce as Odoo's EDI provider and its function as an intermediary for Odoo and non-Odoo systems.
3. Explain the purpose of the 850 inbound transaction for receiving purchase orders from external systems.
4. Describe the 810 outbound transaction’s purpose in sending invoices to external systems.
5. Summarize the setup process: installing the SPS Commerce module, setting up the FTP server, and creating custom EDI mappings.

Task

Forward port: to 17.0 only. EDI is not yet available in 18.0

flowchart TD
    subgraph Buyer["Trading Partner's Environment"]
        B_SYS["ERP Business System"]
        B_EDI["EDI Translator"]
        
        subgraph B_FTP["Trading Partner's FTP Server"]
            B_OUT["Outbound 850 Files"]
            B_IN["Inbound 810 Files"]
        end
    end

    subgraph Supplier["Odoo's Environment"]
        S_EDI["EDI Translator"]
        S_SYS["ERP Business System"]
        
        subgraph S_FTP["Odoo's FTP Server"]
            S_OUT["Outbound - 810 Files"]
            S_IN["Inbound - 850 Files"]
        end
    end

    %% Buyer flows
    B_SYS --> |"Generate PO"| B_EDI
    B_EDI --> |"Upload 850"| B_OUT
    B_IN --> |"Download 810"| B_EDI
    B_EDI --> |"Process Invoice"| B_SYS

    %% Supplier flows
    S_IN --> |"Download 850"| S_EDI
    S_EDI --> |"Process PO"| S_SYS
    S_SYS --> |"Generate Invoice"| S_EDI
    S_EDI --> |"Upload 810"| S_OUT

    %% Cross-server transfers
    B_OUT --> |"Push 850 via SFTP"| S_IN
    S_OUT --> |"Push 810 via SFTP"| B_IN

    classDef ftpServer fill:#f9f,stroke:#333,stroke-width:2px
    class B_FTP,S_FTP ftpServer

[robodoo]

[Felicious]

Followed up with Fernando, and we're planning to freeze this document until the feature is more developed!