moves metric package to /infra

ref #14679

pkg/api/dataproxy.go

@@ -2,7 +2,7 @@ package api
 
 import (
 	"github.com/grafana/grafana/pkg/api/pluginproxy"
-	"github.com/grafana/grafana/pkg/metrics"
+	"github.com/grafana/grafana/pkg/infra/metrics"
 	m "github.com/grafana/grafana/pkg/models"
 	"github.com/grafana/grafana/pkg/plugins"
 )