[enhancement] Support for print file folder structures

[mggevaer]

Currently it's not possible to create folder structures and to upload gcode files to a specific folder. This is possible through Prusa connect. This forces me to do this through prusa-connect where it is possible to create folders.

This is important to me because it allows me to easily and consistently keep track of different print versions. such as:

• customers
  • Customer1
    • some_part
      • v1
        • ...
      • v2
        • x1_some_part_PETG
        • x2_some_part_PRUSA_PC
  • Customer2 ....

I noticed working with folders also isn't the easiest through the Octoprint UI, so this might be something that's not all that important to many people. Just an FYI.

[BaileyMillerSSI]

This would be great! I am used to using OctoPrint with PrusaSlicer and uploading a file into a folder is extremely helpful for organization. I noticed that even though I am using the / in the file name during upload to PrusaConnect it is always being placed at the root of the USB.