[Feat](Exports) Add custom options to exports

Context

Some exports are different. Mine is. However they were not able to express their difference, as some people want the exports to be all the same. This merge request aims to bring back some diversity among exports, by allowing to specify the forward template file to use or the location of exported kernels.

Modified files

• export_registry.py : Add forward templates optional variables for body and header;
• scheduler_export.py : Use forward templates optional variables if not empty to generate the forward files. Add the test_mode optional parameter. This may be replaced in future versions.
• pybind_data.cpp : Binding of get_data_format_transpose function.
• pybind_tensor.cpp : Binding of set_data_format function.
• GraphView.cpp : Add datatype to mermaid file generation.