Add dashboard json data source or add attribute to current dashboard resource

[Shocktrooper]

What resources or data sources are affected?

existing datadog_dashboard datasource
or
new datadog_dashboard_json datasource

Feature Request

I would like the ability to get the json of an existing dashboard which is available in the API but not the provider. This can be added to the current datadog_dashboard datasource or a new datadog_dashboard_json datasource can be created for this

References

https://docs.datadoghq.com/api/latest/dashboards/#get-a-dashboard