Generalization of Mesh Initialization to handle Polygons

- added Polygon specialization for EntitySeed and EntitySeedHash that uses Array instead of StaticArray to handle variable number of cornerIds
- refactored template argument EntityDimensionTag of SubentitySeedsCreator to EntityTopology to allow specializing for Polygons
- added Polygon specialization for SubentitySeedsCreator to handle variable amounts of vertices per polygon
- added getSubentitiesCount function to SubentitySeedsCreator to retrieve number of subentities to be created from passed in vertices
- modified Initializer::initSubentityMatrix function to retrieve capacities from a method argument instead of creating them statically from traits and to pass in retrieved capacities to Mesh::setSubentitiesCounts
- removed EntityInitializer::initSubvertexMatrix function and replaced all calls to it with Initializer::initSubentityMatrix
- modified EntityInitializerLayer::initSuperentities and InitializerLayer::initEntities functions to calculate subentity matrix capacities before a call to Initializer::initSubentityMatrix