cmd/gitmirror: get key from GCE metadata, add a k8s resource controller

Updates golang/go#18817

Change-Id: Iff09e580d720ab1dfc8de0da2c45340467a335db
Reviewed-on: https://go-review.googlesource.com/36473
Reviewed-by: Kevin Burke <kev@inburke.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2 files changed