[FR] Support for external storage (flash drives and so on)

[BlackberrieCake137]

Is your feature request related to a problem? Please describe.
As of right now, there is good SD card support and internal storage, but none of the sort for external storage such as USB drives. This would be super useful with many of us who have massive music collections and can't keep them all on SD cards because our phones and tablets don't support them.

Describe the solution you'd like
Support for the music collections on attached USB drives

Describe alternatives you've considered
This but a toggle if it can be buggy? I'm not known to Android development so I'm not sure of any issues that may be caused.

• I will open one issue per request, follow the issue format and will add [FR] to the start of my issue title, and I acknowledge that if I don't follow the format, my issue might get closed without further explanation.