* Use boundary velocity v_j in term (v_i*v_j) both for upwinding and
  central average
* do not use upwinding for kovasznay test
* update reference solutions for kovasznay and angeli test

[test][staggered][discretization] make test 3d, write out all distance (cell centered and parallel widths)

[cleanup][tests][2pncmin] remove unnecessary salt precipitation from gas phase in the source term as no salt is in the gas phase anyway

[2p][incompressible][tracer] add getParams to spatialParams for permeability to reuse it with different permeabilites for tracer systems

* non-backward compatible change
* store const ref to fvGridGeometry
* call resize() without argument

* adapt test