Philippe 26/11/2020: IO: remove dead code (compatibility of dates with old MNH, not working anymore)

Philippe 24/11/2020: rename NMNHDIM_BUDGET_MASK_TIME -> NMNHDIM_BUDGET_TIME and time_mask -> time_budget

Philippe 13/11/2020: IO: improve CF compliance (add missing unit, does not write empty standard_name)

Quentin 28/10/2020: default value of LRED is now TRUE (LRES = reduction of time dependency of ICE3/ICE4 microphysics scheme)

Quentin 27/10/2020: SURFEX v9, mis-usage of YRECFM (of size = LEN_HREC) variable for a comment variable. In SURFEX offline, LEN_HREC=12 which is not compatible here.

(cherry picked from commit f06a12ec)

(cherry picked from commit 9cd59c0e)

(cherry picked from commit f06a12ec)

(cherry picked from commit 3583de28)

Philippe 15/10/2020: IO: Write_les_budget_n: restructure Les_diachro calls to use tfield_metadata_base type

Philippe 15/10/2020: IO: Write_les_rt_budget_n: restructure Les_diachro calls to use tfield_metadata_base type

Philippe 14/10/2020: IO: Write_les_sv_budget_n: restructure Les_diachro calls to use tfield_metadata_base type

(cherry picked from commit 246ad00d)

(cherry picked from commit 74b8dba9)

(cherry picked from commit 74b8dba9)