review; fix; improve backward-compatibility and state persistence

[panaC]

Change list:

• add a splash-screen when reader registry migration is needed between 330 and 340 for more than 20 publications
• parallelize file storage persistence from 330 to 340 per publication during migration
• parallelize publication reading persistence when reconstructing the final backward-compatible 330 state.json with the reader registry object
• add a visited publication identifier set to publication-data to track change per publication when persisting the final backward compatible 330 state.json (avoid to loop on all publication registry in disk instead)
• fixes hydration of the win.registry.reader state from 330 state.json when persisting the final backward-compatible state on closing

Should Fixes/Improve #3381