Integrate VIRGO genes

Closes #111

TO DO

• Create VIRGO source in the model and have the corresponding migration
• Create all Genes
  • IDs
  • Sequences
  • KEGG annotations
  • EggNOG annotations
  • Taxonomy
• Display source on frontend and possibility to filter

backend/metagenedb/api/catalog/filters/gene.py

@@ -33,4 +33,4 @@ class GeneFilter(filters.FilterSet):
 
     class Meta:
         model = Gene
-        fields = ['length', 'name']
+        fields = ['length', 'name', 'source']