Merge branch 'PhaseField' into 'master'

...cess/PHASE_FIELD/phasefield_parameters/t_history_field.md

...HASE_FIELD/phasefield_parameters/t_kinetic_coefficient.md

...processes/process/PHASE_FIELD/t_irreversible_threshold.md

ProcessLib/PhaseField/CreatePhaseFieldProcess.cpp

ProcessLib/PhaseField/CreatePhaseFieldProcess.h

ProcessLib/PhaseField/PhaseFieldFEM-impl.h

ProcessLib/PhaseField/PhaseFieldFEM.h

ProcessLib/PhaseField/PhaseFieldProcess.cpp

ProcessLib/PhaseField/PhaseFieldProcess.h

ProcessLib/PhaseField/PhaseFieldProcessData.h

ProcessLib/PhaseField/Tests.cmake

Tests/Data/PhaseField/ME01_ext_2D_orth.prj

Tests/Data/PhaseField/ME01_ext_2D_orth.vtu

Tests/Data/PhaseField/ME01_ext_2D_para.prj

Tests/Data/PhaseField/ME01_ext_2D_para.vtu

Tests/Data/PhaseField/bar.gml

Tests/Data/PhaseField/beam/AT2_iso_tensile.prj

Tests/Data/PhaseField/beam/bar.gml

Tests/Data/PhaseField/beam/bar.vtu

Tests/Data/PhaseField/beam/bar_left.vtu