GKB merge
Adds access/implementation of two versions of the Golub-Kahan Bidiagonalization (GKB) solver to HyTeG:
- the GKB implementation from PETSc can be run via PETScBlockPreconditionedStokesSolver
- an own implementation of GKB on HyTeGs datastructures in GKBSolver.hpp
Adds an augmented Lagrangian operator used by the HyTeG implementation of GKB Adds python scripts for the work unit calculation of solver configurations