Harmonize the flat Gene Expression Result files into a single table

[RobertJCarroll]

We need to merge the data from the single-sample files into a single table. Given that we do not know the samples for each assay result, we will need to capture both a sample and a participant identifier. This ticket proposes a "rows are samples" format.

Requirements:

1. Table will be keyed with two fields: Patient and Specimen references. These must be full FHIR URIs for the resources. If missing, the field should be an empty string.
2. The other columns will contain the gene expression data. Values not present will be filled with NA . This is expected given potential lack of overlap in measured genes.