Allow solvebio import to take a dataset capacity argument

[jsh2134]

allow this argument to be passed when creating a new dataset in the import command with the --create-dataset shortcut

a user can already do this with the client by creating a dataset first, just not with the all-in-one command. not sure if we should add this option as well. an alternate approach is to include the capacity in the dataset_template used

[jsh2134]

(customer request)

[dandanxu]

^ it'd be good to know what the possible options are too - is it small, medium, large?

[davecap]

Actually we have tall, grande, and venti.