xref datasets for AGR homolog data

[katewarner]

Related to #2136 xref datasets for new AGR data in protein_homolog_clusters.csv

Source file = ebi/current/uniprot-proteome-$taxa.nt files
Output file =$taxa _protein_xref_alliance_genome_resources.csv
Species datasets = human, rat, mouse, zebrafish, fruitfly, and yeast

The output file should have the following headers:

"id", "xref_key", "xref_id", "xref_label" 

Input file:
AGR xref data for is present in triples within the different taxa's uniprot-proteome-*.nt files e.g.

<http://purl.uniprot.org/uniprot/A0A096MIX7> <http://www.w3.org/2000/01/rdf-schema#seeAlso> <http://purl.uniprot.org/agr/RGD:1561261> .
<http://purl.uniprot.org/uniprot/A0AQH0> <http://www.w3.org/2000/01/rdf-schema#seeAlso> http://purl.uniprot.org/agr/FB:FBgn0010590
<http://purl.uniprot.org/uniprot/A0A075F5C6> <http://www.w3.org/2000/01/rdf-schema#seeAlso> <http://purl.uniprot.org/agr/MGI:96238> .

Output files
There should be seven new $taxa _protein_xref_alliance_genome_resources.csv datasets for human, rat, mouse, zebrafish, fruitfly, and yeast

Example output file: human _protein_xref_alliance_genome_resources.csv

id	xref_key	xref_id	xref_label
A0A087WZT3-1	protein_xref_alliance_genome_resources	HGNC:53563
Q13490-1	protein_xref_alliance_genome_resources	HGNC:590
Q5SWW7-1	protein_xref_alliance_genome_resources	HGNC:31008