refs #850 Add define types for language in constants

src/constants/language/index.d.ts

@@ -0,0 +1,17 @@
+export type LanguageType = {
+  name: string
+  key: string
+}
+
+export type LanguageList = {
+  de: LanguageType,
+  en: LanguageType,
+  fr: LanguageType,
+  ja: LanguageType,
+  ko: LanguageType,
+  pl: LanguageType
+}
+
+declare var l: LanguageList
+
+export default l