Use buildah commit and bud in podman

Vendor in buildah and use as much of commit and bug as possible for podman
build and commit.

Resolves #586
Signed-off-by: baude <bbaude@redhat.com>

Closes: #681
Approved by: mheon

pkg/inspect/inspect.go

@@ -125,6 +125,7 @@ type ImageData struct {
 	RootFS          *RootFS           `json:"RootFS"`
 	Labels          map[string]string `json:"Labels"`
 	Annotations     map[string]string `json:"Annotations"`
+	ManifestType    string            `json:"ManifestType"`
 }
 
 // RootFS holds the root fs information of an image