Usability cleanup for 'inspect'

Make the usage messages (and options) different between
podman inspect, podman image inspect, and podman container inspect.

Disable inapplicable options (-l, -s) for podman image inspect

Disable -t (type) when the type is implicit through the subcommand.

Update man page to reflect differences in usage.

Fix broken test.

Uglier than desirable due to Go and Cobra limitations

Signed-off-by: Ed Santiago <santiago@redhat.com>

cmd/podman/main.go

@@ -42,7 +42,7 @@ var mainCommands = []*cobra.Command{
 	&_imagesCommand,
 	_importCommand,
 	_infoCommand,
-	_inspectCommand,
+	&_inspectCommand,
 	_killCommand,
 	_loadCommand,
 	podCommand.Command,