`paleocontextchildtable` is not set on new Paleo/Geo databases

[alesan99]

Describe the bug
paleoContextChildTable should be defined on the discipline level. This causes (harmless) errors on the backend when loading up the chronostrat tree.
Geo databases should have it set to the Collection Object table, and paleo databases should have it set to Collecting Event (@grantfitzsimmons)

To Reproduce

1. Open up a blank database
2. Set up the database
3. See errors in the backend logs when opening the chronostrat tree. The field paleocontextchildtable is also blank on the discipline.

Expected behavior
The field can be blank on non-paleo/geo tables, but it should be automatically set by default otherwise.
Ideally this field should be customizable during the guided setup and also in the system configuration, but it doesn't need to be.