Implement EZP-21323: Add link to older packages in setup wizard

Issue link: https://jira.ez.no/browse/EZP-21323

Screenshoot:
![screen shot 2013-08-08 at 19 30 19](https://f.cloud.github.com/assets/289757/933140/86c9fd54-0050-11e3-9242-9f05ba4c7edf.png)

Link goes to http://packages.ez.no/ezpublish/ (template gets url from ini setting)