Add support for mwscript-k8s

• Run mwscript-k8s instead of mwscript
• Cleanup the k8s resources after each run to avoid overwhelming the cluster (T376795)
• Switch to kubernetes.client instead of kubectl Could use a more recent version but start with an "old" 12.0.1 version since it is the one installed on wmf machines.
• Introduce two new options to ease testing:
  • verbose to debug the interaction with the kubernetes client API
  • force-reindex to force a reindex even if there are no changes detected
• Use expectedindices API instead of mwscript for most of the wikis (still rely on a maint script to extract the connection info)
• Use the shard_count given by the Cirrus expectedindices API instead of fetching this from the elastic cluster state

Bug: T378382

Depends-On: https://gerrit.wikimedia.org/r/c/operations/puppet/+/1101607