WIP: Update Puppetfile for compatibility with Puppet 7

- Add mailalias_core module
- Add sshkeys_core module
- Add augeas_core module
- Add cron_core module
- Add mount_core module
- Bump zfs_core module to 1.3.0

These modules need to be imported to GitLab for this to be landable

Ref. swh/infra/sysadm-environment#4778