Support new dashboard API

[lexrj]

Hi there,

Terraform Version

11+

Affected Resource(s)

• datadog_screenboard
• datadog_timeboard

Expected Behavior

Datadog API has deprecated the screenboard and timeboard APIs in favor of a unified dashboard API: https://docs.datadoghq.com/api/?lang=bash#dashboards

I would expect the provider to match in this regard. This covers at least two additional behavior:

• GROUP type widgets are not reported by the deprecated Timeboard API but are reported by the Dashboard API; I would expect GROUP type widgets to be supported by this provider
• Only Legacy IDs can be used for terraform import, even though these are hard to find in the UI.

Actual Behavior

At least as a user, it appears that the terraform-provider-datadog maps to the old API.

[bkabrda]

This was added in #249 and will be part of next release (hopefully before end of this week).