Improve robustness of Ansible SSH connections

When running Ansible across many nodes (or over a bad internet connection) one might experience SSH connection issues. If you encounter them, consider improving robustness with:

```
[persistent_connection]
connect_retry_timeout = 30
connect_timeout = 120

[ssh_connection]
retries = 3
ssh_args = -o ControlMaster=auto -o ControlPersist=600s
```