Add export to excel invoices

To the Invoice list: Proforma/All/In Review/Open/Closed was added Export multi button, which contains:

• Export to Excel button -> after clicking on the button, the window for downloading excel is opened and in excel is displayed next columns:
  • Datagrid:
    • Customer Name;
    • Invoice #;
    • Customer PO #;
    • SO #;
    • IR #;
    • Invoice Date;
    • Shipping Address;
    • Billing Address;
    • Tax;
    • Terms;
    • Invoice Status;
    • Order Status;
    • Original Amount;
    • Payment;
    • Open Balance;
    • Brand;
    • Category;
  • Totals:
    • Total Amount;
    • Total Payments;
    • Open Balance;
• Export to Excel with Items button:
  • Datagrid:
    • Customer Name;
    • Invoice #;
    • Customer PO #;
    • SO #;
    • IR #;
    • Invoice Date;
    • Shipping Address;
    • Billing Address;
    • Item;
    • Description;
    • Qty;
    • UOM;
    • Price;
    • Amount;
    • Tax;
    • Terms;
    • Invoice Status;
    • Order Status;
    • Original Amount;
    • Payment;
    • Open Balance;
    • Brand;
    • Category;
  • Totals:
    • Total Amount;
    • Total Payments;
    • Open Balance;

Also was added horizontal scroll to the list form.