Alerting: introduce AlertQuery in definitions package (#63825)

* copy AlertQuery from ngmodels to the definition package
* replaces usages of ngmodels.AlertQuery in API models
* create a converter between models of AlertQuery
---------

Co-authored-by: Alex Moreno <alexander.moreno@grafana.com>

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

@@ -5,8 +5,6 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
-
-	"github.com/grafana/grafana/pkg/services/ngalert/models"
 )
 
 func TestRulePayloadMarshaling(t *testing.T) {
@@ -24,7 +22,7 @@ func TestRulePayloadMarshaling(t *testing.T) {
 		{
 			desc: "success grafana",
 			input: func() TestRulePayload {
-				data := models.AlertQuery{}
+				data := AlertQuery{}
 
 				// hack around that the struct embeds the json message inside of it as well
 				raw, _ := json.Marshal(data)
@@ -33,7 +31,7 @@ func TestRulePayloadMarshaling(t *testing.T) {
 				return TestRulePayload{
 					GrafanaManagedCondition: &EvalAlertConditionCommand{
 						Condition: "placeholder",
-						Data:      []models.AlertQuery{data},
+						Data:      []AlertQuery{data},
 					},
 				}
 			}(),