* apparently, the file content would sometimes not be sent otherwise

* previously, the connection object could time out and cause issues
* also, include the error type in the message

* offers improved error handling
* should be more portable w.r.t. the execution environment

* add support for authentication tokens (required by InvenioRDM 1.0+)
* add switch to not publish created records

* instead, add a script that does a metadata migration between two
  concrete versions of InvenioRDM
* note: it's not guaranteed that the naming w.r.t. the original version
  is accurate... could also have been the january metadata model

* also, actually pass the file names to 'invenio tuw records update ...'

* this prevents the marshmallow schema from transforming the records in
  any way that we wouldn't want (e.g. hiding fields)

InvenioRDM (November Release) runs into errors when the resource_type
does not expect a subtype, but an empty subtype is specified