Refactors AASXPackageManager to use Apache POI library to read .aasx

Adds test to ensure AASXPackageManager can load .aasx files created by the AASXFactory

Signed-off-by: Maximilian Conradi <maximilian.conradi@iese.fraunhofer.de>
Change-Id: Ib2f9e240add0253f0fd508b3edd5fbbe47e48543
5 files changed