Feature/sum factorization on unstructered grids

Make it possible to use sum factorization on unstructured grids. The main problem are the skeleton terms. We need to make sure that we go through the quadrature points in the same order on the two neighboring cells and that (the jacobian of) the geometry function is applied correctly. Instead of looking at all possible embeddings of the face and further increasing the variation we make sure that the grid is made edge consistent. See consistent-edge-orientation module and the paper 'On Orienting Edges of Unstructured Two- and Three-Dimensional Meshes':

• https://gitlab.dune-project.org/marcel.koch/consistent-edge-orientation
• https://dl.acm.org/citation.cfm?doid=3071076.3061708

This merge request does the following:

• make grid edge consistent
• use sum factorization to evaluate the geometry mappings (and jacobians) of the cells
• totally avoid using the geometry mapping of the interesection

Still missing:

• Reordering of directions for 3D at intersections. This needs to be adjusted to make sure that we go thgrough quadrature points on self and neighbor in the same order. For this it would be good to have a 3D grid with consistent edge orientation that shows that this is necessary.
• Vetorization is not yet implemented for GeoCornersInput. We might also need to adjust quadrature point vectorization.