[TASK] Clean up phpDoc comments in typo3/sysext/

Clean up phpDoc comments for the following classes:

* typo3/sysext/impexp/app/index.php
* typo3/sysext/impexp/class.tx_impexp.php

Clean up provides:

* Provide correct parameter names in phpDoc
* Provide correct data types in phpDoc
* CGLify phpDoc (remove tabs)

Change-Id: I72d931829e31d1bcd46ba8efa39fef0275654ef1
Resolves: #38266
Releases: 6.0
Reviewed-on: http://review.typo3.org/12266
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn