bootcache: Add OWNERS file

This CL is populating OWNERS file based on the candidates in the Chrome OS OWNERS status sheet.

BUG=b:132095048
TEST=None

Change-Id: I053461c0b8d0bf4d2ccb0baef8c2484127ee4251
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/bootcache/+/1682552