UX updates

[dysproseum]

Need to make a new action for mobile streaming, the one I modified breaks VLC playback on desktop, although it wasn't working great to begin with.

Restore original actions and make new actions for "seek_stream" and "seek_stream_mobile" for now.

Test cases:

• Download file (downloadfile)
• Download M3U
• Playback from M3U (streamsid) test in VLC and mobile browser
• Stream html5 on desktop (streamsid)
• Stream html5 on mobile (downloadfile) switched to this to prevent "Live broadcast" and allow streaming

Test seeking in all playback cases.