Sounds preference panel improvements

[humdinger]

Here's a suggestion to improve the Sounds preferences panel.

The panel now (hrev33599):

My suggestion mockup:

On top, there's a dropdown menu with already saved profiles plus the entry "Save current profile..." which will open a panel to enter a profile name.
Pressing the trash symbol will delete the currently set profile. When there's <none>, the symbol is "ghosted".
It would be nice if there'd be a "Toggle mute all" profile preconfigured that would overlay the existing settings. I.e., the sound file selection is kept, but every event is muted/unmuted.
Sound profiles and window setting should be kept in ~/config/settings/Sounds/.

There's a new column "Mute" where you can quickly mute an event without having to choose "<none> for it and later having to find and set the sound file again. The symbol appearing then is supposed to be a stroked speaker. Could be improved...

Besides using MediaPlayers controls to play/pause/stop there's also its volume bar. Every individual sound file's volume can be controled with this widget. For this, an attribute is saved to the sound file.

The panel should start larger than it is now and save its window position.

Not visible: The open file dialog should provide a play/pause "pre-listen" button so you can hear it right there instead of again and again having to load/close/play/open when looking for a sound.

[humdinger]

Sounds panel now

[humdinger]

SOunds panel in the future?