adding sneddon static fracture jupyter notebook

...prj/processes/process/PHASE_FIELD/t_hydro_crack_scheme.md

...ocesses/process/PHASE_FIELD/t_pressurized_crack_scheme.md

Documentation/bibliography/other.bib

ProcessLib/PhaseField/Tests.cmake

...ta/PhaseField/kregime_jupyter_notebook/Kregime_Static.gml

...ta/PhaseField/kregime_jupyter_notebook/Kregime_Static.prj

...eld/kregime_jupyter_notebook/Kregime_Static_jupyter.ipynb

...er_notebook/figures/AT1_crackopening_mesh_sensitivity.png

...er_notebook/figures/AT2_crackopening_mesh_sensitivity.png

...egime_jupyter_notebook/figures/Model_sneddon_straight.png