Feature: Introduce locale in web-widget SDK (#871)

* Introduce setLocale in SDK

Co-authored-by: Sojan <sojan@pepalo.com>

app/views/widget_tests/index.html.erb

@@ -5,6 +5,7 @@
 window.chatwootSettings = {
   hideMessageBubble: false,
   position: 'left',
+  locale: 'fr',
 };
 
 (function(d,t) {

app/views/widgets/show.html.erb

@@ -17,6 +17,7 @@
         welcomeTagline: '<%= @web_widget.welcome_tagline %>',
         welcomeTitle: '<%= @web_widget.welcome_title %>',
         widgetColor: '<%= @web_widget.widget_color %>',
+        enabledLanguages: <%= available_locales_with_name.to_json.html_safe %>,
       }
       window.chatwootWidgetDefaults = {
         useInboxAvatarForBot: <%= ActiveModel::Type::Boolean.new.cast(ENV.fetch('USE_INBOX_AVATAR_FOR_BOT', false)) %>,