feature #1142 Add Arabic language translation (khaledalam)

This PR was merged into the master branch.

Discussion
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Add Arabic language translation

Symfony framework is used by a huge number of people who speak Arabic and this PR will be helpful for many people!

Commits
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5545c6f Add Arabic language translation.

Author: javiereguiluz

config/services.yaml

@@ -6,7 +6,7 @@
 parameters:
     locale: 'en'
     # This parameter defines the codes of the locales (languages) enabled in the application
-    app_locales: en|fr|de|es|cs|nl|ru|uk|ro|pt_BR|pl|it|ja|id|ca|sl|hr|zh_CN|bg|tr|lt
+    app_locales: ar|en|fr|de|es|cs|nl|ru|uk|ro|pt_BR|pl|it|ja|id|ca|sl|hr|zh_CN|bg|tr|lt
     app.notifications.email_sender: [email protected]
 
 services: