OfficeImporter does not check for existing documents anymore

Since at least 2.2.x, Office Importer does not check for existing documents anymore and will overwrite even if the document exists regardless of the "append" setting.

The reason is that new APIs have been created that replace importDocument and they don't check the existance of documents.

We can fix either in the velocity script or in the APIs. I believe it would be better to fix in the APIs.