Cast operator pybind

Context

Cast pybind was required for quantized onnx models import.

See aidge_onnx issue: aidge_onnx#42

Modified files

• pybind_Cast.cpp , Added pybind file;
• pybind_core.cpp , Added cast method definition;

requested review from @olivierbichler

changed the description

approved this merge request

enabled an automatic merge when all merge checks for 75d25d42 pass

added Enhancement ⭐ label

mentioned in commit 1fda3d80

merged