allow OS file IO bypass for storage media image format back-ends

[joachimmetz]

To prevent running out of file handles, allow storage media image format that support segment files to bypass the OS file IO (file-like objects) and directly use the back-ends so that the number of open file handles can be throttled. Still support file IO for images-in-images.

• [x] ~~https://github.com/log2timeline/dfvfs/pull/542~~
  • ~~EWF (segment files) - requires experimental libewf version~~
  • ~~Split RAW (segment files)~~
• [ ] VMDK (data extent files)

What about mounted OS paths that contain "mounted" images?

[joachimmetz]

Fix:

BackEndError: Unable to open file system with error: pyewf_glob: unable to glob filenames. libewf_glob: invalid filename length value out of bounds.