Philippe 16/11/2022: profilers: rename VISI -> VISIGUL + compute visibilities only when it has a meaning (there were NaN if not...)

Philippe 27/10/2022: datetime: add <= and > operators and improve older comparison subroutines (more robust but slower)

Philippe 21/10/2022: bugfix: ground_param_n: communicate halo values between processes for OUT variables

+ more efficient use of grid variables

(cherry picked from commit ca071273)

Philippe 04/07/2022: workaroung GCC bug: date_time is not defined as an extended type of date (to prevent failure when reading arrays of date_type in namelists)

Philippe 01/07/2022: add use of optional OLOCAL argument of Print_msg when useful for stations and profilers