AlertingNG: POC of evaluator under feature flag. (#27922)

* New feature toggle for enabling alerting NG

* Initial commit

* Modify evaluate alert API request

* Check for unique labels in alert execution result dataframes

* Remove print statement

* Additional minor fixes/comments

* Fix lint issues

* Add API endpoint for evaluating panel queries

* Push missing renaming

* add refId for condition to API

* add refId for condition to API

* switch dashboard based eval to get method

* add from/to params to dashboard based eval

* add from/to params to  eval endpoint

Co-authored-by: kyle <kyle@grafana.com>

pkg/api/http_server.go

@@ -29,6 +29,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/datasources"
 	"github.com/grafana/grafana/pkg/services/hooks"
 	"github.com/grafana/grafana/pkg/services/login"
+	eval "github.com/grafana/grafana/pkg/services/ngalert"
 	"github.com/grafana/grafana/pkg/services/provisioning"
 	"github.com/grafana/grafana/pkg/services/quota"
 	"github.com/grafana/grafana/pkg/services/rendering"
@@ -70,6 +71,7 @@ type HTTPServer struct {
 	BackendPluginManager backendplugin.Manager            `inject:""`
 	PluginManager        *plugins.PluginManager           `inject:""`
 	SearchService        *search.SearchService            `inject:""`
+	AlertNG              *eval.AlertNG                    `inject:""`
 	Live                 *live.GrafanaLive
 	Listener             net.Listener
 }