[TASK] Sync objectmananger get and create with Flow

ObjectManager::create was deprecated since Flow beta1 and was 
removed for Flow 1.0. To be in sync again deprecate Extbase
ObjectManager::create and use ObjectManager::get.

Change-Id: I5b92bae39ec63fdd985797ff03cb688ea6ff96d3
Resolves: #45322
Releases: 6.1
Reviewed-on: https://review.typo3.org/18162
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Marc Bastian Heinrichs
Tested-by: Marc Bastian Heinrichs