[GUI] Uploading multiple samples to the same IRIDA sample cause errors with upload bars

[JeffreyThiessen]

Describe the bug

Because we decide which progress bar is updated by identifying them by + we only create one progress bar if there are multiple sample sets with the same project id sample id pair.

Steps to reproduce the problem

1. Use the directory uploader with full file paths.
2. Create 2 entries going to the same project/sample
3. Upload

Expected behaviour

Each entry should have it's own progress bar.

Additional context

This should be solved by generating a UUID for each SequenceFile object, and associating the progress bar with it.
The progress signal emitter will need to be changed to emit the UUID instead of the project sample pair.