Add new subroutines in MultiPhysicsProbThermal that can set properties individually

[bishtgautam]

Presently MPPThermalSetSoils() is defined as:

  subroutine MPPThermalSetSoils(thermal_mpp, begc, &
                           endc,               &
                           thermal_filter,                 &
                           thermal_lun_type,               &
                           thermal_watsat,                 &
                           thermal_csol,                   &
                           thermal_tkmg,                   &
                           thermal_tkdry                   &
                           )

sets all properties of soils is set at once.

Add new subroutine(s) that:

• Set properties one at a time.
• Set properties for internal, boundary, and source-sink auxiliary variables.