Add Group Permissions to backup directory and files

[jessecowens]

Is your feature request related to a problem? Please describe.
In certain server environments, notably Cloudways, the SSH user is different from the WordPress (PHP) user

This creates a situation where if one is SSH'd into the site (or using SFTP to store remote backups), the user cannot access backups or the backup directory.

Describe the solution you'd like
Add an option to include group permissions to the backup directory and files, (e.g. 770, 660) so that linux users belonging to the www-data group can access the backups.

Alternatives
It is possible for advanced users to filter the directory permissions with a code snippet, child theme functions.php or a micro-plugin.

Additional context
This feature is related to user feedback found in the WordPress.org forums