Add support for Rocky Linux 8

ansible/group_vars/all/dnf

ansible/group_vars/all/globals

ansible/group_vars/all/infra-vms

ansible/group_vars/all/kolla

ansible/group_vars/all/overcloud-dib

ansible/group_vars/all/seed-vm

ansible/roles/dnf/tasks/local-mirror.yml

ansible/roles/dnf/templates/Rocky-AppStream.repo.j2

ansible/roles/dnf/templates/Rocky-BaseOS.repo.j2

ansible/roles/dnf/templates/Rocky-Extras.repo.j2

dev/functions

doc/source/administration/infra-vms.rst

doc/source/administration/overcloud.rst

doc/source/administration/seed.rst

doc/source/configuration/reference/hosts.rst

doc/source/configuration/reference/network.rst

doc/source/configuration/reference/os-distribution.rst

doc/source/configuration/reference/overcloud-dib.rst

doc/source/configuration/scenarios/all-in-one/index.rst

doc/source/configuration/scenarios/all-in-one/overcloud.rst