Alerting: Support for simplified notification settings in rule API (#81011)

* Add notification settings to storage\domain and API models. Settings are a slice to workaround XORM mapping
* Support validation of notification settings when rules are updated

* Implement route generator for Alertmanager configuration. That fetches all notification settings.
* Update multi-tenant Alertmanager to run the generator before applying the configuration.

* Add notification settings labels to state calculation
* update the Multi-tenant Alertmanager to provide validation for notification settings

* update GET API so only admins can see auto-gen

pkg/services/ngalert/api/api_ruler_test.go

@@ -20,6 +20,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/accesscontrol/acimpl"
 	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
 	"github.com/grafana/grafana/pkg/services/datasources"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/services/folder"
 	"github.com/grafana/grafana/pkg/services/ngalert/accesscontrol"
 	apimodels "github.com/grafana/grafana/pkg/services/ngalert/api/tooling/definitions"
@@ -603,10 +604,24 @@ func createService(store *fakes.RuleStore) *RulerSrv {
 		cfg: &setting.UnifiedAlertingSettings{
 			BaseInterval: 10 * time.Second,
 		},
-		authz: accesscontrol.NewRuleService(acimpl.ProvideAccessControl(setting.NewCfg())),
+		authz:          accesscontrol.NewRuleService(acimpl.ProvideAccessControl(setting.NewCfg())),
+		amConfigStore:  &fakeAMRefresher{},
+		amRefresher:    &fakeAMRefresher{},
+		featureManager: &featuremgmt.FeatureManager{},
 	}
 }
 
+type fakeAMRefresher struct {
+}
+
+func (f *fakeAMRefresher) ApplyConfig(ctx context.Context, orgId int64, dbConfig *models.AlertConfiguration) error {
+	return nil
+}
+
+func (f *fakeAMRefresher) GetLatestAlertmanagerConfiguration(ctx context.Context, orgID int64) (*models.AlertConfiguration, error) {
+	return nil, nil
+}
+
 func createRequestContext(orgID int64, params map[string]string) *contextmodel.ReqContext {
 	defaultPerms := map[int64]map[string][]string{orgID: {datasources.ActionQuery: []string{datasources.ScopeAll}}}
 	return createRequestContextWithPerms(orgID, defaultPerms, params)