feat: Enhance email functionality and PDF generation for Sales Orders

- Enabled SMTP debugging in PHPMailer for better error tracking.
- Added a "Test send email" link in the Inventory Detail View for quick email testing.
- Implemented automatic PDF generation and email sending upon Sales Order creation.
- Created a new action for sending Sales Order emails with attached PDFs.
- Added a new AJAX action for testing outgoing email server configurations.
- Updated outgoing server settings to use new SMTP credentials.
- Improved email templates for better user experience.
- Added test scripts for validating PDF generation and email sending.

layouts/v7/skins/sales/style.css

@@ -1881,6 +1881,7 @@ th {
   margin: 0px 1px !important;
 }
 .referencefield-wrapper .createReferenceRecord {
+  display: none !important;
   float: left;
   margin-left: 5px;
   margin-top: 3px;