Convert some notebooks from ipynb to py

ProcessLib/HydroMechanics/Tests.cmake

ProcessLib/LiquidFlow/Tests.cmake

ProcessLib/PhaseField/Tests.cmake

ProcessLib/SmallDeformation/Tests.cmake

ProcessLib/TH2M/Tests.cmake

ProcessLib/Tests.cmake

Tests/Data/HydroMechanics/SeabedResponse/Stationary_waves.py

Tests/Data/Mechanics/CooksMembrane/CooksMembraneBbar.py

...iscWithHole/Linear_Disc_with_hole_convergence_analysis.py

Tests/Data/Mechanics/Linear/SimpleMechanics.py

Tests/Data/Mechanics/PLLC/PLLC.py

.../BlockingConductingFracture/BlockingConductingFracture.py

...opagating_jupyter_notebook/Kregime_Propagating_jupyter.py

...ata/PhaseField/PForthotropy_jupyter_notebook/sen_shear.py

Tests/Data/PhaseField/beam_jupyter_notebook/beam.py

...eField/kregime_jupyter_notebook/Kregime_Static_jupyter.py

...ta/PhaseField/surfing_jupyter_notebook/surfing_pyvista.py

Tests/Data/PhaseField/tpb_jupyter_notebook/TPB.py

Tests/Data/TH2M/H/diffusion/diffusion.py

Tests/Data/TH2M/H2/dissolution_diffusion/phase_appearance.py