Auto-Update gitea mirrors

[tibeer]

Create a zuul job to periodically update the mirros on gitea

[tibeer]

Related sources:

• https://github.com/osism/public-services/blob/main/.playbooks/update-gitea-mirrors.yaml
• https://github.com/osism/public-services/blob/main/scripts/mirror.py
• https://github.com/osism/scripts/tree/main/gitea (outdated)