Builds a lowercased, trimmed tuple from the identifying fields
(resource_type, vendor, catalog_number, lot_number, rrid, doi, accession).
Two resources with the same signature are considered duplicates.
Examples
r <- new_resource("Antibody", "Anti-TH", vendor = "Millipore",
catalog_number = "AB152", new_or_reuse = "reuse")
resource_signature(r)
#> [1] "resource_type\037antibody\037vendor\037millipore\037catalog_number\037ab152\037lot_number\037\037rrid\037\037doi\037\037accession\037"
