Provide a way to configure home directory permissions

On Debian-based systems, users' home directories are world-readable by default. This is counterintuitive, this is appaling, yet this is set in stone by being that way for decades. Still, the user deserves a way to secure own files from others.

I believe an option should be added to set the default permission policy ("allow other users to read home directory" or something like that) which will also trigger update on user-created files' permissions by changing them corresponding to the new umask.

Shall I try and make a patch like this?

No files, tests, or entry points are named. Start by locating how this settings plug creates or updates users and handles home-directory permissions, then determine the project’s existing umask and permission APIs; done would require an agreed policy option and defined behavior for existing user-created files.

Written by the indexing model from the issue text.