tflite: Add DIR_METADATA and OWNERS

CL for updating CQ config: https://crrev.com/i/6937754
CL for updating manifest: https://crrev.com/i/6938753

BUG=b:314854484
TEST=Run `dirmd validate` and pass presubmit check in manifest-internal

Change-Id: Ibbd29b35e84b7d7d718f124948383572c3240f68
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/tflite/+/5267423
Commit-Queue: Shik Chen <shik@chromium.org>
Reviewed-by: Chih-Yang Hsia <paulhsia@chromium.org>
Reviewed-by: Tommy Chiang <ototot@google.com>
Tested-by: Shik Chen <shik@chromium.org>