Remove custom time unit conversion in favor of UDUNITS

[mattw-nws]

The following exists:

ngen/include/realizations/catchment/Bmi_Adapter.hpp

Lines 93 to 107 in c317184

	void acquire_time_conversion_factor(double &time_convert_factor) {
	std::string time_units = GetTimeUnits();
	if (time_units == "s" || time_units == "sec" || time_units == "second" || time_units == "seconds")
	time_convert_factor = 1.0;
	else if (time_units == "m" || time_units == "min" || time_units == "minute" ||
	time_units == "minutes")
	time_convert_factor = 60.0;
	else if (time_units == "h" || time_units == "hr" || time_units == "hour" || time_units == "hours")
	time_convert_factor = 3600.0;
	else if (time_units == "d" || time_units == "day" || time_units == "days")
	time_convert_factor = 86400.0;
	else
	throw std::runtime_error(
	"Invalid model time step units ('" + time_units + "') in " + model_name + ".");
	}

The BMI docs for get_time_units state:

It’s recommended to use time unit conventions from Unidata’s UDUNITS package; e.g., "s", "min", "h", "d".

Replace the time unit conversion code above with the use of UnitsHelper/UDUNITS for consistency.

Bonus/Future: Consider an optimization for the case when the native units of the model are seconds? UnitsHelper does this somewhat, but it might be worthwhile to highly optimize this function that is called every timestep.

Current behavior

time units are converted with bespoke internal code which may not be consistent with UDUNITS conversion

Expected behavior

unit conversions are consistent across the application and with UDUNITS as suggested by the BMI docs.

Steps to replicate behavior (include URLs)

Screenshots