Allow the use of GR2M and GR1A models

This issue needs a update of airGR. This last does not allow the use of SD models with monthly and yearly time steps: https://gitlab.irstea.fr/HYCAR-Hydro/airgr/-/blob/dev/R/CreateInputsModel.R#L138

On airGRiwrm side, a priori, we just need to complete the following function in order to add the number of seconds for a monthly and a yearly time step: https://gitlab.irstea.fr/in-wop/airGRiwrm/-/blob/531701b5041047c1e019a9e0371f9b0c6fdca55b/R/CreateInputsModel.GRiwrm.R#L371

This is tricky since months and years don't have the same length. Mixing mm / time step for hydrological models and m3/time step for human influences may interfere in the results.

A "LagZero" model could be useful in order to do not bother the model with lag calibration when it's not needed (especially for yearly time step).