Dr/vfs close files

[dr-frmr]

Problem

VFS would never close file handles, leading to resource misuse.

Solution

Add a task to intermittently check if a file is in recent use, and if not, close it.

Testing

Use system as normal

Docs Update

N/A

Notes

This does not (unless I'm confused) fix the issue with immediate attempts to reuse the same file. @bitful-pannul