Restore upstream mirrors in container image package repos

[markgoddard]

Currently the Kolla container images configure Yum repositories to use
pulp-server on SMS Cloud:

(nova-compute) $ grep baseurl /etc/yum.repos.d/CentOS-Stream-BaseOS.repo
baseurl=http://pulp-server.internal.sms-cloud:8080/pulp/content/centos/8-stream/BaseOS/x86_64/os/20211122T102435

This makes it difficult to install/update packages for debugging issues
in customer environments.

This change restores Yum repository files at the end of the container image
build to point to distribution repositories. It also makes an attempt to
do the same for Apt repos, although these are not enabled in Wallaby
currently.

[markgoddard]

Tested here: https://github.com/stackhpc/stackhpc-kayobe-config/actions/runs/4689189856

[markgoddard]

Tested here: https://github.com/stackhpc/stackhpc-kayobe-config/actions/runs/4689189856

Tested out the image:

[centos@skc-builder-runner ~]$ docker run -u0 --rm -it --net=host 94df4f5bb497 bash
()[glance@skc-builder-runner /]$ grep -r baseurl /etc/yum.repos.d/ | grep pulp
()[glance@skc-builder-runner /]$ dnf upgrade