Train molecule jobs in tripleo-ansible have to use podman driver

[Sagi (Sergey) Shnaidman]

Currently it's impossible to install both podman and docker on the same host in CentOS 8, so we need to migrate all train molecule jobs to use podman driver.
The workaround is to use install_docker_c8:false in jobs definition to skip docker install, but driver should be podman in this case.

[chandan kumar (chkumar246)]

On this review https://review.opendev.org/c/openstack/tripleo-ansible/+/767481 and https://zuul.opendev.org/t/openstack/build/8cf8bf44feca44b498d97ec631e9e456 - /tripleo-ansible-centos-8-molecule-tripleo_lvmfilter on stable/train failed with

Depsolve Error occured:
 Problem: problem with installed package podman-1.6.4-23.module_el8.3.0+566+4759265c.x86_64
  - package podman-1.6.4-23.module_el8.3.0+566+4759265c.x86_64 requires runc >= 1.0.0-57, but none of the providers can be installed
  - package containerd.io-1.4.3-3.1.el8.x86_64 conflicts with runc provided by runc-1.0.0-64.rc10.module_el8.3.0+479+69e2ae26.x86_64
  - package containerd.io-1.4.3-3.1.el8.x86_64 obsoletes runc provided by runc-1.0.0-64.rc10.module_el8.3.0+479+69e2ae26.x86_64
  - cannot install the best candidate for the job
  - package runc-1.0.0-68.rc92.module_el8.3.0+475+c50ce30b.x86_64 is filtered out by modular filtering

it is coming at this place: https://opendev.org/zuul/zuul-jobs/src/branch/master/roles/ensure-docker/tasks/docker-upstream.yaml#L32