Draft: New reco classes

The merge request introduces new (experimental) structures for reconstructed data (hits, tracks, PV), which are supposed to be used simultaneously in online and offline reconstruction regimes.

TODO:

• Hit classes
• Track class and container
• PV class and container
• RecoData container [WIP]
• Example filling task [WIP, TODO: add tracks, PV]
• Example QA task [WIP, TODO: add tracks, PV]
• Integration to online
• Testing: IO