Moving SMPI app deployment to C++ code

Moving SMPI app deployment to C++ code

Enable the deployment of SMPI experiments with C++ platform description.
Move application deployment from smpirun to smpi_main function.

The smpirun script used to parse the platform XML to create an
application deployment. This isn't possible anymore since we may don't
have a platform XML anymore.

Move the necessary input to smpi_main through specific cfg variables:
- smpi/hostfile: host file
- smpi/replay: replay file
- smpi/np: number of processes
- smpi/map: mapping process/rank

This cfg isn't used by users, they are cached inside the smpirun script.