Add GET /api/v1/instance/languages to REST API (#24443)

Co-authored-by: Eugen Rochko <eugen@zeonfederated.com>
Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/presenters/language_presenter.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class LanguagePresenter < ActiveModelSerializers::Model
+  attributes :code, :name, :native_name
+
+  def initialize(code)
+    super()
+
+    @code = code
+    @item = LanguagesHelper::SUPPORTED_LOCALES[code]
+  end
+
+  def name
+    @item[0]
+  end
+
+  def native_name
+    @item[1]
+  end
+end