RBAC for alert rule provisioning APIs

The Alerting Provisioning HTTP API has been updated to enforce Role-Based Access Control (RBAC).

For Grafana OSS, users with the Editor role can now use the API.
For Grafana Enterprise and Grafana Cloud, users with the role Rules Writer and Set Provisioning status can access the API and limit access to alert rules that use a particular data source.
Other roles related to provisioning, for example Access to alert rules provisioning API still work.