Add shader input attributes to the shader generation key

This is a partial back-port of dev. RHI already has this feature.
When the user provides different inputs with same shader states and
some inputs are missing, Quick3D makes warnings and can fall into
an unexpected state.
For CustomMaterial, the inputs should be guaranteed by the user.

Change-Id: I53123f1040ae1535e72e20e0769f59b020b696a2
Reviewed-by: Andy Nichols <andy.nichols@qt.io>