workflow-ify lab data model maintenance scripts

[dpark01]

Create new workflow to manage lab data model post demux. This entails a few key to-dos:

1. Improve naming of current existing data model (sample, sample_set, sample_set_set) now that we know how to create relational links between differently named Terra tables
2. Convert all notebook code to WDL in order to greatly improve (and make consistent) the user experience
3. Have separate WDL tasks for introspection and data model maintenance.
4. Implement initially as a standalone workflow -- maybe some day include at the end of demux_deplete but not initially.
5. Current scope: just support Terra-on-GCP (and be able to nop properly if introspection shows we're not in that environment). Eventually support Terra-on-Azure/WDS as well.