Feat: Process orphaned coe clusters for K8S jobs

Feat: Process orphaned coe clusters for K8S jobs

K8s jobs by default creates stacks names that does not match
JOB_NAME, therefore ignore them while processing orphaned stacks
and handle them separatly when cleaning up the orphaned clusters.

The stack naming scheme is limited to take first 20 chars from the
JOB_NAME while the rest is randomly generated for uniqueness which
breaks the openstack cron jobs.

Ref: https://github.com/openstack/magnum/blob/master/magnum/
drivers/heat/driver.py#L202-L212

Issue-ID: RELENG-4106
Change-Id: Id3d9b74c3e6e2a0abbddb771b7fc7d5ba2b59ca5
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>