+(*)Fix problems with generic_tracer_min_max

  Revise MOM_generic_tracer_min_max and array_global_min_max to fix several
problems that had previously been noted, and to make the location arguments
optional, reflecting that they are optional in the calling routine.  This
requires a revision to the order of arguments to MOM_generic_tracer_min_max.
The interface to array_global_min_max was extensively revised and simplified to
replace several previous arguments with a single new ocean_grid_type argument,
to make the location arguments optional, and add an optional unscale argument.

  This commit fixes a number of problems that had previously been noted with
array_global_min_max, including that:
 (1) It actually returns the global minimum and maximum values of the tracer;
 (2) It gives a position that is independent of the domain decomposition
     and grid rotation;
 (3) For all-zero arrays it correctly reports 0 for the minimum and maximum;
 (4) It properly handles unscaling of the input array;
 (5) It does not use a 3-d mask array that is actually just a 2-d mask array;
 (6) It is more efficient by grouping the global minimum and maximum calls.

  This commit also adds or reviss comments to document the units and purpose
of the remaining undocumented real variables in MOM_generic_tracer.F90.

  These changes were tested and verified to be correct by calling
array_global_min_max for temperatures and salinities from write_energy, but
those changes were not included in this commit.

  This commit also adds an optional verbosity argument to g_tracer_flux_init in
config_src/external/GFDL_ocean_BGC/generic_tracer_utils.F90, reflecting a change
to ocean_BGC/generic_tracers/generic_tracer_utils.F90 that was adopted in August
of 2020, and is uses this new verbosity argument in the call from
MOM_generic_flux_init.

  While all solutions are bitwise identical, there are changes (corrections) in
some diagnostic output, and there are changes to the arguments of publicly
visible routines.

config_src/external/GFDL_ocean_BGC/generic_tracer_utils.F90

@@ -99,8 +99,9 @@ module g_tracer_utils
 contains
 
   !> Unknown
-  subroutine g_tracer_flux_init(g_tracer)
+  subroutine g_tracer_flux_init(g_tracer, verbosity)
     type(g_tracer_type), pointer :: g_tracer !< Pointer to this tracer node
+    integer, optional, intent(in) :: verbosity !< A 0-9 integer indicating a level of verbosity
   end subroutine g_tracer_flux_init
 
   !> Unknown