The example should be the same for both .cpp and .cu, otherwise the
output might be inconsistent (e.g. when .cpp is included, but .cu is
compiled and its output is used).

Fixed Jacobi and SOR so that code using getLinearSolver() and a distributed matrix can be compiled (even if the solvers do not work...)

Added dummy methods reduceRows, reduceAllRows, forElements, forAllElements, forRows, forAllRows to DistributedMatrix

The IsArrayType trait does not include TNL::String...

Polygonal + polyhedral mesh

See merge request !93

It was broken because the MeshBuilder interface was changed due to
polygonal and polyhedral meshes, but tnl-decompose-mesh was not built on
the CI due to a missing optional dependency (metis).

See MR !107

- refactored a few for cycles in EntityInitializer to use ParallelFor
- modified function findEntitySeedIndex in Initializer to use find instead of insert
- modified FPMAReaderTest to use slightly bigger mesh for testing
- added a few explanatory comments
- deleted unused methods from SubentitySeedsCreator
- created specialization of Formatter in Assert.h for std::pair to avoid compilation error caused by calling inplaceExclusiveScan on array of pairs

Added EntityInitializerLayer specialization for initializing polyhedron subentites 3 -> 2 from cell seeds + other minor mesh refactoring

Refactored mesh initialization to reduce number of calls to SubentitySeedsCreator and number of dynamic allocations

removed redundant subentitiesCounts array from SubentityStorageLayer of dimension 1 for polygonal meshes

Meshes/Geometry: refactored polygon and polyhedron decomposition into templated EntityDecomposer struct with specializations

- added function getPlanarMesh for correcting non-planar polygons in 3D polygon and polyhedral meshes
- added unit tests for getPlanarMesh function
- refactored getDecomposedMesh specialization for polygons by creating PolygonDecomposer struct to reuse decomposing logic in getPlanarMesh function
- other minor refactoring in Meshes/MeshGeometryTest.h

- modified getEntityMeasure specialization for polyhedrons to remove restriction regarding the ordering of vertices, but now it only works for convex polyhedrons
- added function for decomposing polygonal mesh into triangular mesh
- added function for decomposing polyhedral mesh into tetrahedral mesh

- added getEntityMeasure specializations for 2D and 3D polygon, pyramid, wedge, polyhedron
- added unit tests for new getEntityMeasure specializations
- added function isPlanar for checking whether all points of a 3D polygon are on the same plane
- added unit test for function isPlanar
- refactored isDynamicTopology type trait to avoid warning