This adds `--automated` and `--no-automated` flags to all Zulip
management commands, whose default is based on if STDIN is a TTY.
This enables cron jobs and supervisor commands to continue to report
to Sentry, and manually-run commands (when reporting to Sentry does
not provide value, since the user can see them) to not.
Note that this only applies to Zulip commands -- core Django
commands (e.g. `./manage.py`) do not grow support for `--automated`
and will always report exceptions to Sentry.
`manage.py` subcommands in the `upgrade` and `restart-server` paths
are marked as `--automated`, since those may be run semi-unattended,
and they are useful to log to Sentry.
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