feat(tax): add endpoints to create tax regions and tax rates (#6533)

**What**
Adds:
- POST /admin/tax-regions
- POST /admin/tax-rates
- GET /admin/tax-rates
- `createTaxRegionsWorkflow`
- `createTaxRatesWorkflow`

packages/types/src/tax/common.ts

@@ -22,6 +22,18 @@ export interface TaxRateDTO {
    * Holds custom data in key-value pairs.
    */
   metadata: Record<string, unknown> | null
+  /**
+   * The id of the Tax Region the rate is associated with.
+   */
+  tax_region_id: string
+  /**
+   * Flag to indicate if the Tax Rate should be combined with parent rates.
+   */
+  is_combinable: boolean
+  /**
+   * Flag to indicate if the Tax Rate is the default rate for the region.
+   */
+  is_default: boolean
   /**
    * When the Tax Rate was created.
    */
@@ -30,6 +42,10 @@ export interface TaxRateDTO {
    * When the Tax Rate was updated.
    */
   updated_at: string | Date
+  /**
+   * When the Tax Rate was deleted.
+   */
+  deleted_at: Date | null
   /**
    * The ID of the user that created the Tax Rate.
    */