[MPM] Friction option added to slip condition

[lauramoremar]

Added a Friction penalty option to the usual slip conforming boundary condition:

• By default Friction is off.
• The current writeprojectparameters.tcl writes:

{
            "python_module" : "apply_mpm_slip_boundary_process",
            "kratos_module" : "KratosMultiphysics.MPMApplication",
            "process_name"  : "ApplyMPMSlipBoundaryProcess",
            "Parameters"    : {
                "model_part_name"           : "Background_Grid.Slip_Auto1",
                "friction_coefficient"      : 0.001,
                "tangential_penalty_factor" : 1000000.0,
                "option"                    : "flip_normal"
            }
        }

• Added a cleanup step in writeprojectparameters.tcl for the MPM slip boundary process to remove friction controls from the generated ProjectParameters.
• When friction is disabled, the slip process is written as before.

[ncrescenzio]

Thanks @lauramoremar!