Download ECCOMetadata in parallel?

[glwagner]

I think it might speed things up rather than doing the downloads in serial:

ClimaOcean.jl/src/DataWrangling/ECCO/ECCO_metadata.jl

Lines 184 to 206 in 1280a9d

	for data in metadata
	filename = metadata_filename(data)
	shortname = short_name(data)
	if !isfile(filename)
	msg = "\n See ClimaOcean.jl/src/ECCO/README.md for instructions."
	isnothing(username) && throw(ArgumentError("Could not find the username for $(url). Please provide a username in the ECCO_USERNAME environment variable." * msg))
	isnothing(password) && throw(ArgumentError("Could not find the username for $(url). Please provide a password in the ECCO_PASSWORD environment variable." * msg))
	# Version specific download file url
	if data.version isa ECCO2Monthly || data.version isa ECCO2Daily
	fileurl = joinpath(url, shortname, filename)
	elseif data.version isa ECCO4Monthly
	year = string(Dates.year(data.dates))
	fileurl = joinpath(url, shortname, year, filename)
	end
	cmd = `wget --http-user=$(username) --http-passwd=$(password) --directory-prefix=$(path) $(fileurl)`
	run(cmd)
	end
	end