ci(lts): add script to triage commits

This adds initial version of a script which looks for keywords in a
given patch and determines whether it's a candidate for long term
support (lts). See README for more info.

Signed-off-by: Okash Khawaja <okash@google.com>
Change-Id: Ic469a9000571a87b57c6da8862270fa8d9a8d094
2 files changed