Improve read_data wrapper

[adperezm]

The wrapper to write and read currently checks the partitioning of each key (For HDF5 in particular). This allows to write anything, but the MPI operations can potentially make it slow. This is completely redundant if I know the shapes in advance.

• Keep the wrappers as they are, but allow it receive every argument needed as an input.
• Make sure that the interface for writing and reading is similar - Therefore create a partitioning object that coordinates the difference when reading or writing.