Enable missing containerd plugin

Sandboxes plugin is mandatory and otherwise containerd clients fail
to discover the runtime service. Other plugins like streaming,
transfer and nri, are not enabled although they are included in
containerd 1.7.

services/containerd.go

@@ -17,6 +17,7 @@ import (
 	"github.com/containerd/containerd/mount"
 	_ "github.com/containerd/containerd/pkg/cri"
 	"github.com/containerd/containerd/plugin"
+	_ "github.com/containerd/containerd/plugins/sandbox"
 	_ "github.com/containerd/containerd/runtime/restart/monitor"
 	_ "github.com/containerd/containerd/runtime/v2"
 	_ "github.com/containerd/containerd/runtime/v2/runc/options"