media-viewer: Add audio and video support

* implemented audio and video files support

Youtube embeds takes a teeny while to load but it works.

* properly defined videos in the demo folder

* media-viewer: Refactored audio + video code

* Added video/audio folder/file icons

* media-viewer: Updated youtube view

---------

Co-authored-by: Prozilla <[email protected]>

Author: Lansa-18