Templatize import

The import process has been rewritten to support a more generic import.  

Now, rather than choosing header bookends, choose a Template file (YAML) that defines the trait columns and mappings to the data model

This changeset also adds support for importing additional columns as metadata attached to an OTU (e.g. entry_email, notes, entry name, etc) - basically any data that should be attached to the record but is not trait data, taxonomy, or reference information.