Add EnableCDI() method to engine.Interface

This change adds an EnableCDI method to the container engine config files and
Updates the 'nvidia-ctk runtime configure' command to use this new method.

Signed-off-by: Christopher Desiniotis <cdesiniotis@nvidia.com>

pkg/config/engine/api.go

@@ -20,6 +20,7 @@ package engine
 type Interface interface {
 	AddRuntime(string, string, bool) error
 	DefaultRuntime() string
+	EnableCDI()
 	GetRuntimeConfig(string) (RuntimeConfig, error)
 	RemoveRuntime(string) error
 	Save(string) (int64, error)