FAIR Data Station import should be able to support nested extended metadata

[stuzart]

It is possible to define the nested attributes in flat form within the template and fair data station configuration.
However, when importing it should be able to match these attributes by the pid - but currently doesn't as it skips over them.

To fix, it needs to traverse into the linked nested extended metadata type attributes to find a match and then set the value.

In addition, the discovery of the matching extended metadata type should be extended to include the nested attributes when trying to find the closest match.