Final MR for distributed solves

CMakeLists.txt

examples/distributed/HelmholtzCheckerboard/CMakeLists.txt

examples/distributed/HelmholtzCheckerboard/main.cpp

examples/distributed/Poisson2DRobin/CMakeLists.txt

examples/distributed/Poisson2DRobin/main.cpp

src/field/DistributedField.cpp

src/problem/Formulation.cpp

src/problem/Formulation.h

src/system/MatrixFactory.cpp

src/system/MatrixFactory.h

src/system/Solver.cpp

src/system/VectorFactory.cpp

src/system/VectorFactory.h

unitTests/correctness/CMakeLists.txt

.../correctness/distributedPoisson1DDirichlet/CMakeLists.txt

unitTests/correctness/distributedPoisson1DDirichlet/main.cpp

...ess/distributedPoisson1DLagrangeMultiplier/CMakeLists.txt

...rrectness/distributedPoisson1DLagrangeMultiplier/main.cpp

...Tests/correctness/distributedPoisson2DORAS/CMakeLists.txt

unitTests/correctness/distributedPoisson2DORAS/main.cpp