Display a progress bar when attaching the blob to a document

Current Situation

There is the current blue progress bar that allows one to follow the progression of the uploaded blob. But then, the upload in the systray menu is just here, "waiting for nothing".

In fact, uploads are done in 2 steps:
1. Upload the file (by chunk or normal mode).
2. Attach the uploaded blob to a document.

The blue progress bar is only managed at step 1.

The step 2 may take some time depending of the server workload and the blob size as the server will have to merge all chunks into 1 binary blob.

Proposal

We could leverage the second progress bar (green, used for downloads checksum integrity) for the step 2.
We also need to document those progress bars with screenshots.

Idea = "finalizing" word and progress bar...