Alerting: Rule version history API (#99041)

* implement store method to read rule versions

* implement request handler

* declare a new endpoint

* fix fake to return correct response

* add tests

* add integration tests

* rename history to versions

* apply diff from swagger CI step

Signed-off-by: Yuri Tseretyan <yuriy.tseretyan@grafana.com>

---------

Signed-off-by: Yuri Tseretyan <yuriy.tseretyan@grafana.com>

pkg/services/ngalert/api/forking_ruler.go

@@ -124,3 +124,7 @@ func (f *RulerApiHandler) getService(ctx *contextmodel.ReqContext) (*LotexRuler,
 	}
 	return f.LotexRuler, nil
 }
+
+func (f *RulerApiHandler) handleRouteGetRuleVersionsByUID(ctx *contextmodel.ReqContext, ruleUID string) response.Response {
+	return f.GrafanaRuler.RouteGetRuleVersionsByUID(ctx, ruleUID)
+}