starpu: add common functions to restructure the codelets by wrapping the stapu_mpi_data_task_echange functions and define a function to set common options to the tasks

starpu: detect the starpu_mpi_exchange_data_before_execution function to enable/disable the submit interface

starpu: Try to split what can be public if the user wants to add its own insert_task functions from what needs to remain private

Otherwise, it triggers:
```
runtime/starpu/codelets/codelet_gemmex.c:176:13: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  176 |     cl_name = chameleon_codelet_name( cl_name, 3,
```

The _ex() version allows to provide a task name, which is useful when
using StarPU's profiling interface.