Complete per Tile allocation

[nicolasaunai]

• also having a Tiled representation of all rank data, not just per patch
• dealing tile ghosts exchange for fields (overlaps? per cell?)
• diagnostics tiles to patch dumps
• restart with tiles?
• refinement/coarsening/selection : indexing data can hit multiple tiles, do we have an abstraction of the indexing that fetches data the right tile under the hood...
• modify the "transformers" to operate (sequentially at this point) per tile views instead of per patch