i18n: Missing translation "Add Organization"

See: http://osticket.com/forum/discussion/85083/osticket-sends-no-html-mails#latest

Looked at crowdin and the term "Add Organization" is already used in the following context:
#: include/staff/templates/org-lookup.tmpl.php:82

So my suggestion is to use it also for this context here, which would not require a new translation ;)

Michael