Improve the tagging and the track information handling in the CD ripper.

* Use the TagReaderClient to tag the files in the CD ripper instead of using Taglib directly.

* For each track to be ripped, collect the track number, title, and filename in a struct. This way we only need to keep track of a single list during the ripping/transcoding/tagging process.

* Because of the above change, the signal JobOutputName from the transcoder is no longer necessary and therefore removed. The signal was added together with the CD ripper in #4113 to get the name of the transcoded file and has never been used anywhere else. 

* Capture log messages from the transcoder. They are now sent to Clementine's main log. It may not be optimal but it's better than to discard them completely.