[test] Add test for 2p rotation-symmetric toroid policy unstr. grid

test/porousmediumflow/2p/implicit/CMakeLists.txt

...ousmediumflow/2p/implicit/rotationsymmetry/CMakeLists.txt

test/porousmediumflow/2p/implicit/rotationsymmetry/dome.geo

test/porousmediumflow/2p/implicit/rotationsymmetry/dome.msh

test/porousmediumflow/2p/implicit/rotationsymmetry/main.cc

...orousmediumflow/2p/implicit/rotationsymmetry/params.input

.../porousmediumflow/2p/implicit/rotationsymmetry/problem.hh

...rousmediumflow/2p/implicit/rotationsymmetry/properties.hh

...orousmediumflow/2p/implicit/rotationsymmetry/solution.png

...smediumflow/2p/implicit/rotationsymmetry/spatialparams.hh

test/references/test_2p_rotationsymmetry_dome-reference.vtu