Fix for missing tau neutral PFO links
The container for TauNeutralParticleFlowObjects (Pi0s) was missing after the r22 migration. This was due to a bug in the new tau algorithm. The read handle for the CaloClusterContainer from the calo cluster maker has also been moved to the algorithm (TauRunnerAlg), rather than being in the tool TauPi0ClusterCreator.
Fixes JIRA ticket: https://its.cern.ch/jira/browse/ATLASRECTS-5128