* feat(connector): connector queries and APIs
* chore(connectors): remove type from DB schema design and fix code accordingly
* chore(connectors): put connector as ConnectorInstance's property
* chore(connector): put connector as optional property of ConnectorInstance
* chore: add boolean type for postgres
* chore: remove bool
* feat: connector DB
* fix: remove identifier
* chore: genenrate
* chore: remove data
* chore: todo
* chore: test TODO