add support for v2 DataONE API.
add test for invalid dryad content -- should be rejected because it is not schema valid.
clean up dryad test doc - only use D1 api. https://projects.ecoinformatics.org/ecoinfo/issues/6419
test for inserting dryad instance doc. https://projects.ecoinformatics.org/ecoinfo/issues/6419
initial basic test of inserting dryad metadata. NOTE: uses metacat api, not dataone api. https://projects.ecoinformatics.org/ecoinfo/issues/6419