Add kg2_json_to_kgx_tsv.py to Rule TSV

[acevedol]

I'm currently running kg2-json_to_kgx_tsv.py manually when the build is finished running. This should ideally be included in Rule TSV.

Rule TSV currently generates the TSVs for loading into Neo4j, so I also need to rename the files for clarity.

[acevedol]

Rule TSV is in Snakefile-post-etl