Fortran and python API for the output of a complete restart in T2D

Since the recent merge of the restart_t2d branch, telemac2d outputs a complete restart at full precision in a dedicated file.
In the T2D API's, for the sake of flexibility, there are different API's for the computational part of a timestep and for the output of the graphical results. The approach has to be completed by the introduction of an API for the output of the restart in its own file. The API has to be extended to python Apy's as well.