Add the ability to delete a track

[angristan]

• [x] Add a delete button on profile.php
• [x] Delete using AJAX
• [x] Deletes audio file
• [x] Delete cover file
• [x] Delete track from track table
• [x] Delete track from inclusion table
• [x] Delete track from listening table
• [x] Delete track from likes table
• [x] Delete track div from DOM after deletion
• [x] Put the delete button in a modal

[stephane-rbn]

I think it should be the highest priority. If you think that it will be fast, let's go.