To port `MeshMaterialSynchronizer::synchronizeMaterialsInCells()` with the accelerator API

[DavidDureau]

Is it possible to port the synchronizeMaterialsInCells() with the accelerator API?

Indeed, when a code is running with AcceleratorRuntime=cuda, then the main part of synchronizeMaterialsInCells() is running on CPU and the mat_presence.synchronize() is "running" on GPU, which implies H<->D transfers.

We have ported the same kind of algorithm in a code so we have an example.

[grospelliergilles]

Yes it is possible. I add it to the TODO list.