MPI-dev [WIP]

[dc-luo]

Additions and hotfixes to support MPI for mesh partitioning in fenics

• Hotfixes for AugmentedVector and set_local_from_global, get_global to handle the case where the vector is an AugmentedVector.
• Added parallel unit tests for AugmentedVector and mpiUtils to check these
• RiskMeasure objects that use hippylib.Random are now properly constructed with the mpi rank/size coming from the mesh MPI communicator (Future work should aim to separate out the sampling from the risk measure itself)

To support these changes, we also restructured the directory structure to be more logical and avoids potential circular imports. Namely, we have split soupy/modeling into soupy/modeling, soupy/risk and soupy/cost

• soupy/modeling retains the objects related to constructing controlModel, i.e. the PDE and QoI objects. Also currently holds AugmentedVector since this is a fundamental data structure
• soupy/risk holds RiskMeasure and its specific instances. New risk measures are expected to go here
• soupy/cost holds ControlCostFunctional and related objects, as well as Penalization.

Documentation is updated to reflect these changes