Drag and Drop & Copy-Paste upload support

[ramiroaisen]

Add DnD & Copy-Paste support to playlist and station profile pages, to upload audio files or to upload station profile images.

User's should be able to add files either by drag and dropping them into the appropiate boxes or by copy-pasting.

There should be a clear indication that the user is able to drop the file(s) when they drag content through the page.