Reorganize demos

...is_fenics_finite_strain_elastoplasticity-checkpoint.ipynb

...is_fenics_finite_strain_elastoplasticity-checkpoint.ipynb

...train_elastoplasticity/LogarithmicStrainPlasticity.mfront

...in_elastoplasticity/finite_strain_plasticity_solution.png

.../GenericBehaviour/LogarithmicStrainPlasticity-generic.hxx

...ity/include/TFEL/Material/LogarithmicStrainPlasticity.hxx

...FEL/Material/LogarithmicStrainPlasticityBehaviourData.hxx

...L/Material/LogarithmicStrainPlasticityIntegrationData.hxx

...asticity/mgis_fenics_finite_strain_elastoplasticity.ipynb

...rain_elastoplasticity/results/finite_strain_plasticity.h5

...in_elastoplasticity/results/finite_strain_plasticity.xdmf

...stoplasticity/src/LogarithmicStrainPlasticity-generic.cxx

...lastoplasticity/src/LogarithmicStrainPlasticity-generic.d

...lastoplasticity/src/LogarithmicStrainPlasticity-generic.o

...rain_elastoplasticity/src/LogarithmicStrainPlasticity.cxx

...strain_elastoplasticity/src/LogarithmicStrainPlasticity.d

...strain_elastoplasticity/src/LogarithmicStrainPlasticity.o

demos/finite_strain_elastoplasticity/src/Makefile.mfront

demos/finite_strain_elastoplasticity/src/libBehaviour.so

demos/finite_strain_elastoplasticity/src/targets.lst