feat: add discount functionality to sales and purchase transactions

- Introduced discount_type and discount fields in Bills and SalesReceipts controllers.
- Updated database migrations to include discount and discount_type in estimates and credit notes tables.
- Enhanced SaleReceipt and SaleEstimate models to support discount attributes.
- Implemented formatting for discount amounts in transformers and PDF templates.
- Updated email templates to display discount information.

This commit enhances the handling of discounts across various transaction types, improving the overall functionality and user experience.

packages/server/src/services/CreditNotes/CreditNoteTransformer.ts

@@ -21,6 +21,8 @@ export class CreditNoteTransformer extends Transformer {
       'discountAmountFormatted',
       'discountPercentageFormatted',
       'adjustmentFormatted',
+      'totalFormatted',
+      'totalLocalFormatted',
       'entries',
       'attachments',
     ];
@@ -86,7 +88,6 @@ export class CreditNoteTransformer extends Transformer {
     return formatNumber(credit.amount, { money: false });
   };
 
-
   /**
    * Retrieves formatted discount amount.
    * @param credit 
@@ -120,6 +121,28 @@ export class CreditNoteTransformer extends Transformer {
     });
   };
 
+  /**
+   * Retrieves the formatted total.
+   * @param credit 
+   * @returns {string}
+   */
+  protected totalFormatted = (credit): string => {
+    return formatNumber(credit.total, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the formatted total in local currency.
+   * @param credit 
+   * @returns {string}
+   */
+  protected totalLocalFormatted = (credit): string => {
+    return formatNumber(credit.totalLocal, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
   /**
    * Retrieves the entries of the credit note.
    * @param {ICreditNote} credit