api/services/instrospection: add PluginInfo

The new `PlunginInfo()` call can be used for instrospecting the details
of the runtime plugin.

```console
$ ctr plugins inspect-runtime --runtime=io.containerd.runc.v2 --runc-binary=runc
{
    "Name": "io.containerd.runc.v2",
    "Version": {
        "Version": "v2.0.0-beta.0-XX-gXXXXXXXXX.m",
        "Revision": "v2.0.0-beta.0-XX-gXXXXXXXXX.m"
    },
    "Options": {
        "binary_name": "runc"
    },
    "Features": {
        "ociVersionMin": "1.0.0",
        "ociVersionMax": "1.1.0-rc.2",
        ...,
    },
    "Annotations": null
}
```

The shim binary has to support `-info` flag, see `runtime/v2/README.md`

Replaces PR 8509 (`api/services/task: add RuntimeInfo()`)

Co-authored-by: Derek McGowan <derek@mcg.dev>
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

cmd/ctr/commands/run/run.go

@@ -128,8 +128,9 @@ var Command = cli.Command{
 			Usage: "Enable cni networking for the container",
 		},
 	}, append(platformRunFlags,
-		append(append(commands.SnapshotterFlags, []cli.Flag{commands.SnapshotterLabels}...),
-			commands.ContainerFlags...)...)...),
+		append(commands.RuntimeFlags,
+			append(append(commands.SnapshotterFlags, []cli.Flag{commands.SnapshotterLabels}...),
+				commands.ContainerFlags...)...)...)...),
 	Action: func(context *cli.Context) error {
 		var (
 			err error