Test snapshot logic to aid in customer migrations

[ggilmore]

Necessary for https://app.hubspot.com/contacts/2762526/company/419771425

• Test out https://github.com/sourcegraph/infrastructure/tree/d5aef89769c523010ba130097307ac2265998690/cmd/sourcegraph-server-gen to see if it still works to help customers migrate data when switching from Helm to purl yaml https://github.com/sourcegraph/deploy-sourcegraph.

• Translate the above to Bash