When this option is set to `true`, the backend will automatically get
initialized during the backup process. This applies to invoking
`autorestic backup` or when `autorestic cron` actualy performs a backup.
* feat(backend): add requireKey option to backend
This option will prevent `autorestic` from generating a key and will
cause it to crash instead. This is intended for use cases where you want
to provision the key yourself and don't want `autorestic` to
accidentally generate one for you.
* doc(backend): document requireKey
