Fixed #323 Allow users to select a language in settings (GRN-17) (#324)

* <Added ui for language setting and migration>

* <Option to choose languages added>

* <Fixed code style>

* <Added Rspec tests>

* <sync db>

* <Sync db>

* <Generalized language settings>

* <Fixed flash message>

* Fixed las issue with i18n fallback

* <Modified fallback config>

* <Fixed code style>

config/locales/en.yml

@@ -77,6 +77,15 @@ en:
     video: Watch our tutorial on using Greenlight
     upgrade: Show me how to upgrade to 2.0!
     version: We've released a new version of Greenlight, but your database isn't compatible.
+  language_options:
+    default: Default (browser language)
+    ar: Arabic
+    de: German
+    el: Greek
+    en: English
+    es: Spanish
+    fr: French
+    pt-br: Portuguese (Brazil)
   ldap_error: Unable to connect to the LDAP server. Please check your LDAP configuration in the env file and ensure your server is running.
   login: Sign in
   max_concurrent: The maximum number of concurrent sessions allowed has been reached!
@@ -101,7 +110,7 @@ en:
       or: or
       with: Sign in with %{provider}
     rename_recording:
-      
+
     rename_room:
       name_placeholder: Enter a new room name...
   name_update_success: Room name successfully changed!
@@ -144,6 +153,7 @@ en:
   settings:
     account:
       fullname: Fullname
+      language: Language
       provider: Provider
       image: Image
       image_url: Profile Image URL