Merge branch 'user-account-created-email' into 'master'

Only send "Account was created for you" email when created by admin.

See #1985

cc @sytse

See merge request !1517

app/models/user.rb

@@ -559,7 +559,7 @@ class User < ActiveRecord::Base
   def post_create_hook
     log_info("User \"#{self.name}\" (#{self.email}) was created")
-    notification_service.new_user(self, @reset_token)
+    notification_service.new_user(self, @reset_token) if self.created_by_id
     system_hook_service.execute_hooks_for(self, :create)
   end