Add support for adding dashboards to Grafana Cloud

[JorTurFer]

Hi, We are introducing automations in KEDA for the performance testing infrastructure and the dashboards to share the results are one of the things to automatize (we want to share them publicly, so we have to prepare dashboards and IaC seems like the good approach). OSS provider has support for importing dashboards using terraform, but Grafana Cloud doesn't support it.