Alerting: Foundations of historian app. (#114463)

We have two historians in alerting - alert state and notification. The intention
of this app is to provide query capabilities for both.

In this initial commit, the existing /history API is simply cloned to the new
app. It is identical except that it will send Kubernetes-style error responses
instead of Grafana-style.

This approach was taken to implement the new app more iteratively - ideally we
would define a new API, but this requires quite a significant overhaul of the
backend code.

pkg/registry/apps/wireset.go

@@ -3,6 +3,7 @@ package appregistry
 import (
 	"github.com/google/wire"
 
+	"github.com/grafana/grafana/pkg/registry/apps/alerting/historian"
 	"github.com/grafana/grafana/pkg/registry/apps/alerting/notifications"
 	"github.com/grafana/grafana/pkg/registry/apps/alerting/rules"
 	"github.com/grafana/grafana/pkg/registry/apps/annotation"
@@ -25,6 +26,7 @@ var WireSet = wire.NewSet(
 	correlations.RegisterAppInstaller,
 	rules.RegisterAppInstaller,
 	notifications.RegisterAppInstaller,
+	historian.RegisterAppInstaller,
 	logsdrilldown.RegisterAppInstaller,
 	annotation.RegisterAppInstaller,
 	example.RegisterAppInstaller,