Make Zoltan-Based Domain Partitioning MPI Aware

This commit switches the current implementation of
'partitionCellsZoltan()', i.e., 'partitionCells("zoltan", ...)' into
using the MPI-aware ParallelNLDDPartitioningZoltan utility.  In
doing so we make 'partitionCellsZoltan()' private since its
availability is not guaranteed.  We also slightly reorder the
parameters and switch from passing a "Grid" into passing a
"GridView" as an argument to partitionCells(), and specialise this
function for the known grid views in OPM Flow.

We extract the Zoltan-related parameters out to an Entity-dependent
helper structure and move the complexity of forming this type to a
new helper function, BlackoilModelEbosNldd::partitionCells().

opm/simulators/utils/ParallelNLDDPartitioningZoltan.cpp

@@ -195,7 +195,7 @@ namespace {
             return static_cast<int>(this->graph_.numVertices());
         }
 
-        /// Retrieve globally unqique ID of reachable vertex.
+        /// Retrieve globally unique ID of reachable vertex.
         ///
         /// \param[in] localCell Index of locally reachable cell/vertex.
         int globalId(const int localCell) const
@@ -422,7 +422,7 @@ extern "C" {
         ///
         /// \param[in] comm MPI communicator.
         ///
-        /// \param[in] params Control parameters for Zoltan graph partiitioning procedure.
+        /// \param[in] params Control parameters for Zoltan graph partitioning procedure.
         explicit Partitioner(const Opm::Parallel::Communication                         comm,
                              const Opm::ParallelNLDDPartitioningZoltan::ZoltanParamMap& params);
 

opm/simulators/utils/ParallelNLDDPartitioningZoltan.hpp

@@ -74,7 +74,7 @@ namespace Opm {
 
         /// Force collection of cells to be in same result domain.
         ///
-        /// Mostly as a way to ensuring wells do not intersect multiple
+        /// Mostly as a means to ensuring wells do not intersect multiple
         /// domains/blocks.
         ///
         /// \param[in] cells Cell collection.  Typically those cells which