#691 Subtitles downloads broken on read-only directories

[Niluge_KiWi]

When playing a video from a read-only directory, the subtitles download feature doesn't work, because it tries to save the subtitles alongside the played file.

"It wasn't possible to save the downloaded
file in folder /read-only-directory
Please check the permissions of that folder"

In such cases subtitles could be downloaded to a temporary file in /tmp to make this work.
Or there could be a prompt to save the file somewhere else.