Automating the heterogenous deployment step: https://wikitech.wikimedia.org/wiki/Heterogeneous_deployment/Train_deploys#Sync_to_cluster_and_verify_on_testwiki
Currently we rebuild l10n by syncing to test wiki. We should rebuild before the train before syncing anywhere
- Rebuild l10n for a specified version via scap
- Automate this rebuild command to run prior to a deployment window
- Pre-sync the tree (without update wikiversions.json)