The "metalsmith-integration-glance-netboot-cirros-direct" job was
removed over 3 years ago. Since this branch is going EOL soon, simply
drop the job.
Also make the openstacksdk-functional-devstack-networking job non-voting
since it is failing too often, drop the
dib-nodepool-functional-openstack-centos-8-stream-src job which is no
longer supported in nodepool and stop running non-voting jobs in gate.
Change-Id: I5348efd5eb13258192baf1a6b324f0b6d956ce38
ce55da7ede