merge from 2.6 branch: add support for EML 2.1.1 to DC crosswalking for OAI provider. https://projects.ecoinformatics.org/ecoinfo/issues/7030
merge from 2.6 branch: add support for EML 2.1.1 to DC crosswalking for OAI provider. https://projects.ecoinformatics.org/ecoinfo/issues/7030