Add support for tax inclusivity to region and store (#7808)

This also includes rework of the currency model for the Store module.

This change is breaking as existing stores won't have any supported currencies set, so users would need to go to the store settings again and choose the supported currencies there.

integration-tests/helpers/seed-storefront-defaults.ts

@@ -29,8 +29,9 @@ export const seedStorefrontDefaults = async (
 
   store = await storeModule.updateStores(store.id, {
     default_region_id: region.id,
-    supported_currency_codes: [region.currency_code],
-    default_currency_code: region.currency_code,
+    supported_currencies: [
+      { currency_code: region.currency_code, is_default: true },
+    ],
   })
 
   return {