Merge pull request #11786 from VannTen/cleanup/unused_ci_test_files

docs/developers/ci.md

tests/files/packet_centos8-calico-ha-once-localhost.yml

tests/files/packet_centos8-calico-ha.yml

tests/files/packet_centos8-flannel-addons-ha.yml

tests/files/packet_centos8-multus-calico.yml

tests/files/packet_centos8-weave-upgrade-ha.yml

tests/files/packet_ubuntu20-docker-weave-sep.yml

tests/files/packet_ubuntu22-all-in-one-docker.yml

tests/files/packet_ubuntu24-all-in-one-docker.yml

tests/files/packet_ubuntu24-calico-all-in-one.yml

tests/files/vagrant_centos8-kube-router.rb

tests/files/vagrant_centos8-kube-router.yml

tests/files/vagrant_ubuntu20-weave-medium.rb

tests/files/vagrant_ubuntu20-weave-medium.yml