Used / Total GB used (Disk widget) information suggestion (pull req.)

[LGDL]

Hi,

I wanted to see used / total GB in the Disk widget, so I modified it and submitted a pull request.

If anyone needs this too, you can modify the Disk.js file directly too, here are the changes I've proposed (hoping it will make it in a future update):

https://github.com/opnsense/core/pull/9131