[2p2c] Port model and tests to next

dumux/porousmediumflow/2p2c/implicit/indices.hh

dumux/porousmediumflow/2p2c/implicit/model.hh

...x/porousmediumflow/2p2c/implicit/primaryvariableswitch.hh

dumux/porousmediumflow/2p2c/implicit/properties.hh

dumux/porousmediumflow/2p2c/implicit/propertydefaults.hh

dumux/porousmediumflow/2p2c/implicit/volumevariables.hh

dumux/porousmediumflow/2p2c/implicit/vtkoutputfields.hh

test/porousmediumflow/2p2c/implicit/injectionproblem.hh

test/porousmediumflow/2p2c/implicit/test_2p2c_fv.cc

test/porousmediumflow/2p2c/implicit/test_2p2c_fv.input

test/porousmediumflow/2p2c/implicit/test_2p2cni_fv.input

test/porousmediumflow/2p2c/implicit/test_box2p2c.cc

test/porousmediumflow/2p2c/implicit/test_box2p2c.input

test/porousmediumflow/2p2c/implicit/test_box2p2cni.cc

test/porousmediumflow/2p2c/implicit/test_box2p2cni.input

...usmediumflow/2p2c/implicit/test_box2p2cni_reference.input

test/porousmediumflow/2p2c/implicit/test_cc2p2c.cc

test/porousmediumflow/2p2c/implicit/test_cc2p2cni.cc

...ousmediumflow/2p2c/implicit/test_cc2p2cni_reference.input

test/porousmediumflow/2p2c/implicit/test_ccmpfa2p2c.cc