Add new more biosample terms from IHCC DAC survey

[beckyjackson]

• plasma sample
• cerebrospinal fluid (CSF)
• cells (is this too general? You can get cells from many different biosamples)

[beckyjackson]

@mcourtot do you know what the survey means by "cells"? Are these cultured cell lines? Or are these from another anatomical source, e.g. the skin, bone marrow, etc.?

Maybe it's best if I add both "tissue" sample and "cells", where "cells" means a cell culture?