support importing txt playlist

[rhjdvsgsgks]

Is your feature request related to a problem? Please describe. i want to subscribe to some playlist which only avaliable in txt format

Describe the solution you'd like add support for txt playlist

Describe alternatives you've considered convert txt playlist to m3u?

Additional context a example of txt formated playlist can be found at https://github.com/xzhhbx/IPTV-3/blob/master/IPTV.txt