Extract default geometry traits from MultiLinearGeometryTraits

Summary

The MultiLinearGeometry can be parametrized by traits that are defaulted to MultiLinearGeometryTraits. Several other geometry implementations might use the same or at least a subset of these traits, e.g. various implementations of courved or chained geometries. This MR extracts some common traits properties into a separate class that can better be used by other geometries. Additionally, the FieldMatrixHelper class is extracted from the affine geometry into a separate file to be reused by multiple geometry implementations.