New test subset script

[MattWellie]

A big ol' ton of changes

• Changes all the queries from individual API queries to GraphQL queries. The number of queries could probably be shrunk down even further with some thought
• Updates/Writes still use the fixed API endpoints/models
• Arguments loosened up to allow any combination of #random samples, #random families, specific families and specific samples

I've got a fair bit of remaining uncertainty here - the original script had participants, samples, families, this one requires a different definition of Sample, and requires Sequencing Groups as an additional layer

[vivbak]

Hey Matt, sorry does this overlap much with this PR? #519

[MattWellie]

See #519