Added DoubleLayerCapacity for incompressible mixture

examples/DoubleLayerCapacity/Lambda.py

examples/DoubleLayerCapacity/Molarity.py

examples/DoubleLayerCapacity/Solvation.py

examples/DoubleLayerCapacity/ValidationAnalyticalMethod.py

...es/DoubleLayerCapacity/__pycache__/Helper.cpython-312.pyc

src/Helper_DoubleLayerCapacity.py

src/__pycache__/Eq02.cpython-312.pyc

src/__pycache__/Helper_DoubleLayerCapacity.cpython-312.pyc