Alerting: extend rules export API to filter by folder and group (#74423)

update endpoint `GET /api/v1/provisioning/alert-rules/export` to accept query parameters `folderUid` and `group`

pkg/services/ngalert/api/tooling/definitions/provisioning.go

@@ -9,7 +9,7 @@ type AlertingFileExport struct {
 	Policies      []NotificationPolicyExport `json:"policies,omitempty" yaml:"policies,omitempty"`
 }
 
-// swagger:parameters RouteGetAlertRuleGroupExport RouteGetAlertRuleExport RouteGetAlertRulesExport RouteGetContactpointsExport RouteGetContactpointExport
+// swagger:parameters RouteGetAlertRuleGroupExport RouteGetAlertRuleExport RouteGetContactpointsExport RouteGetContactpointExport
 type ExportQueryParams struct {
 	// Whether to initiate a download of the file or not.
 	// in: query

pkg/services/ngalert/api/tooling/definitions/provisioning_alert_rules.go

@@ -71,6 +71,20 @@ import (
 //     Responses:
 //       204: description: The alert rule was deleted successfully.
 
+// swagger:parameters RouteGetAlertRulesExport
+type AlertRulesExportParameters struct {
+	ExportQueryParams
+	// UID of folder from which export rules
+	// in:query
+	// required:false
+	FolderUID string `json:"folderUid"`
+
+	// Name of group of rules to export. Must be specified only together with folder UID
+	// in:query
+	// required: false
+	GroupName string `json:"group"`
+}
+
 // swagger:parameters RouteGetAlertRule RoutePutAlertRule RouteDeleteAlertRule RouteGetAlertRuleExport
 type AlertRuleUIDReference struct {
 	// Alert rule UID