Add a resource for group attribute mapping

[IevaVasiljeva]

Adding a resource for group attribute mapping feature.

Requires grafana/grafana-openapi-client-go#103 to be merged first, so that we can bump the openAPI client dependency.

Here is an example of how the new resource can be used to map a role to a group:

resource "grafana_role" "report_admin_role" {
  name                   = "Report Administrator"
  uid                    = "report_admin_role_uid"
  auto_increment_version = true
  permissions {
    action = "reports:create"
  }
  permissions {
    action = "reports:read"
    scope  = "reports:*"
  }
}

resource "grafana_group_attribute_mapping" "report_admin_mapping" {
  group_id  = "business_dev_group_id"
  role_uids = [grafana_role.report_admin_role.uid]
}

[github-actions]

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To do so, a Grafana Labs employee must trigger the cloud acceptance tests workflow manually.

[IevaVasiljeva]

I couldn't make it to automatically infer types, but I am not sure why. Let me know if you have any ideas.

[IevaVasiljeva]

Looks like the openAPI spec has changed slightly for alerting.

[IevaVasiljeva]

Waiting for #1905 to be merged (it updates the openAPI client dependency). Will then rebase on top of that and fix any remaining issues.