cros-provision: Create empty place holder fro CLI.

BUG=b:199943048
TEST=build

Change-Id: Iad435911f6fcc12162263b2b9385c7d9ba2dda7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/3210513
Commit-Queue: Otabek Kasimov <otabek@google.com>
Commit-Queue: Derek Beckett <dbeckett@chromium.org>
Commit-Queue: Seewai Fu <seewaifu@google.com>
Tested-by: Otabek Kasimov <otabek@google.com>
Auto-Submit: Otabek Kasimov <otabek@google.com>
Reviewed-by: Derek Beckett <dbeckett@chromium.org>
Reviewed-by: Seewai Fu <seewaifu@google.com>