Show file transfers/thumbnails within conversation windows
Please note by far the quickest way to get a new feature is to file a Merge Request.
Description of the new feature
Most recent clients show file transfers from contacts as a message in the conversation. This essentially makes the file transfer an actual part of the conversation. Gajim opens a side window with all the transfers, and an additional popup dialog when the file has finished.
While there is no issue with the side window with all the transfers, it would be great to get rid of the popup dialog.
In addition, it would provide a more immediate feedback to also show the transfer in the conversation window (maybe only if a conversation with that contact is open, though opening the conversation would also make sense), interleaved with between the messages that came before, and those that came after.
Once the file has been received, if it is a recognised MIME type, an adequate preview (e.g., a thumbnail) could also be placed in place of the transfer widget.
This should be the case for both incoming and outgoing file transfers.