Refactor localization language model

Author: Velord

model/src/commonMain/kotlin/com/velord/model/localization/LanguageCode.kt

@@ -0,0 +1,15 @@
+package com.velord.model.localization
+
+import kotlinx.serialization.Serializable
+
+@JvmInline
+@Serializable
+value class LanguageCode(val value: String) {
+    init {
+        require(value.isNotBlank()) { "Language code must not be blank" }
+    }
+
+    companion object {
+        val English = LanguageCode("en")
+    }
+}