Integrate JSON schemas for DecisionTable objects #798

Context:

• Initial Decision Table object #795 created a DecisionTable object but we have not yet addressed its JSON schema

Hint:

print(json.dumps(base.DecisionTable.model_json_schema(),indent=2))

We probably just need to dump this into data/schema/v2/Decision_Table-2-0-0.schema.json and link it to data/schema/current/Decision_Table.schema.json.

The schema dump part probably belongs in doctools.py as a separate method.