Improve `reports/tables` tables

[gaurav]

PR #624 added a babel_outputs/reports/tables directory that includes some tables. Since this was created in a hurry for the Babel/ORION paper, some issues crept in and needed to be fixed manually. This issue collects those fixes, as well as suggestions for future improvements that will probably end up being moved into its own issue.

• Add a table summary of the overall metadata files.
• GeneFamily.txt.yaml doesn't include identifier counts, which would be good to have.
• Publication.txt.yaml should include a PMID count.
• ubergraph.build_sets() (exact) of MONDO:0000001 and MONDO:0042489 is a bit vague
• build_protein_uniprotkb_ensemble_relationships -- typo