feat(i18n): add 'similarProducts' key to multiple language files

- Introduce 'similarProducts' translation key across various language files to enhance product detail pages.
- Update existing translations for improved clarity and consistency in product descriptions.
- Ensure proper localization support for the new key in Arabic, Bulgarian, Czech, Greek, French, Croatian, Hungarian, Italian, Polish, Romanian, Russian, Slovak, Slovenian, Albanian, Serbian, Swedish, Turkish, Ukrainian, and Chinese.

src/i18n/locales/bg/product.js

@@ -14,7 +14,7 @@ export default {
   "arriving": "Пристигане:",
   "inclVatFooter": "вкл. {{vat}}% ДДС,*",
   "availability": "Наличност",
-  "inStock": "налично",
+  "inStock": "налично на склад",
   "comingSoon": "Очаква се скоро",
   "deliveryTime": "Срок на доставка",
   "inclShort": "вкл.",
@@ -28,6 +28,7 @@ export default {
   "individualPriceTotal": "Обща индивидуална цена:",
   "setPrice": "Цена на комплекта:",
   "yourSavings": "Вашите спестявания:",
+  "similarProducts": "Подобни продукти",
   "countDisplay": {
     "noProducts": "0 продукта",
     "oneProduct": "1 продукт",