Feature/istl paramtree
What this MR does / why does DuMux need it:
This MR adds a class for creating a parameter tree needed for the dune istl solvers and preconditioners.
At can be used by the IstlSolverFactoryBackend and by a SeqSolverBackend.
The corresponding code in IstlSolverFactoryBackend is removed.
Special notes for your reviewer: @timok @bernd
Do we want LinearSolverTraits as template parameter?
So far it is only used to extract dim for AMG.
The traits are currently not passed to the SeqSolverBackends.
I did not notice any difference between setting setDefaultValuesIsotropic(dim)
and not setting anything.
BlockDiagAMGBiCGSTABSolver has setDefaultValuesIsotropic(3)hard-coded.
Edited by Timo Koch