[FEATURE] Upload/download files

[jordan-dalby]

Is your feature request related to a problem? Please describe.
Not a problem necessarily, but with the addition of fragments, file names can now be entered alongside a code snippet which means that they can now be bundled into downloadable files, in the same respect, files could be uploaded straight into ByteStash, with auto-detection of the language based on the extension (or stretch goal, file contents)

Describe the solution you'd like
An upload and download button

Describe alternatives you've considered

Additional context