support Rule in Export item

It's now possible to provide Rules in Export items.

Change-Id: I0d96fdb570842c08f7a25284296052e40900b4a7
Task-number: QBS-583
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
support FileTagger in Export item

It's now possible to provide FileTaggers in Export items.

Task-number: QBS-583
Change-Id: I178c06be0f80e529ec278ecf7059e0da78cbe6b5
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>