Add video and audio support in Bulk Optimization

[bfintal]

Currently we only perform bulk optimization on image files (jpg, webp and png). Let's add video and audio support as well.

Optimization should be performed the following way:

• the video and audio formats should retain their original file format (mp4 optimizes to mp4). this is unlike when uploading a video, they always get converted to mp4 (e.g. mov gets converted to mp4)
• the video and audio settings in Cimo will be followed during conversion
• only the video and audio file types supported by browsers should show up in the bulk optimization list. For example, if our video optimization doesn't support .mov files, then .mov files should not appear in the bulk optimization file list
• during optimization, there is no need to show a modal with a progress of the optimization per file like how it happens during instant optimization
• other functions by bulk optimizing images should work with video and audio as well: skipping, backup, deleting of backups, etc