Factor out upsert and upsertAndWait

It's a common pattern in the create commands to construct a value,
then (if not exporting it) upsert it and wait for it to
reconcile. This commit factors `upsert`, which does the update/insert
bit, and `upsertAndWait`, which does the whole thing.

Since these output messages, they are methods of `apiType` (previously
`names`), so that they have access to the name of the kind they are
operating on.

Signed-off-by: Michael Bridgen <michael@weave.works>

cmd/flux/resume_image_updateauto.go

@@ -30,8 +30,8 @@ var resumeImageUpdateCmd = &cobra.Command{
   flux resume image update latest-images
 `,
 	RunE: resumeCommand{
-		names:  imageUpdateAutomationNames,
-		object: imageUpdateAutomationAdapter{&autov1.ImageUpdateAutomation{}},
+		apiType: imageUpdateAutomationType,
+		object:  imageUpdateAutomationAdapter{&autov1.ImageUpdateAutomation{}},
 	}.run,
 }