VFS File permission support

[milankovic88]

I have managed to set up os-js to use PAM authentication, but it seems that os-js doesn't respect file permissions with multiple users.

It would be nice if os-js file manager would respect file permissions.

[andersevenrud]

Without using ACL or some sort of system group combo for both the user and the user the node server runs as, it seems like I have to split out the VFS backend.

This way the VFS can run as a separate privileged service on the side. I've started doing a bit of proof-of-concept on this, and I'll let you know when I have something :)