Add table turbot_notifications

[Joeturbot]

References
Turbot docs on Notifications: https://turbot.com/v5/docs/concepts/notifications
API Refernce for Notifications: https://turbot.com/v5/docs/reference/graphql/query/notifications
Notification Definition: https://turbot.com/v5/docs/reference/graphql/object/Notification

To get Activity information out of Turbot, you need access to the Notifications table.

[alex-elam]

Business use case: identify the number of events by workspace or business.
We are attempting to understand the number of enforcement actions taken across workspaces/businesses in an aggregate manner for analytics purposes.