Handling erroneous or xarray incompatible FieldSet netcdf metadata

[VeckoTheGecko]

We need to decide to what extent we want to support broken or xarray incompatible metadata in Parcels (e.g., for units).

I am of the mindset that we rely on the user to fix their metadata using xarray before passing it to Parcels (though we can help out with informative error messages).

For the meantime I am going to remove code along the lines of

Parcels/parcels/tools/converters.py

Lines 240 to 254 in 85d9ee7

	def convert_xarray_time_units(ds, time):
	"""Fixes DataArrays that have time.Unit instead of expected time.units"""
	da = ds[time] if isinstance(ds, xr.Dataset) else ds
	if "units" not in da.attrs and "Unit" in da.attrs:
	da.attrs["units"] = da.attrs["Unit"]
	da2 = xr.Dataset({time: da})
	try:
	da2 = xr.decode_cf(da2)
	except ValueError:
	raise RuntimeError(
	"Xarray could not convert the calendar. If you're using from_netcdf, "
	"try using the timestamps keyword in the construction of your Field. "
	"See also the tutorial at https://docs.oceanparcels.org/en/latest/examples/tutorial_timestamps.html"
	)
	ds[time] = da2[time]

so that we can consolidate this later

[erikvansebille]

Yep, agree! Let users make sure their array datasets are compatible. Maybe add tooling as a separate layer later on, but not within Parcels-Core