[Feature] Use Powder Web as Streaming Engine

[jaruba]

Move all streaming related code to Powder Web: https://github.com/jaruba/PowderWeb

This will act as Powder Player's separate torrent manager and streaming engine.

It's important to make this change as it would make it very easy to add support for new protocols to both apps at the same time. It's also useful for increased torrent seed time, as it would continue to seed torrents even after Powder Player would be closed.

Roadblocks:

• ~youtube-dl is currently supported in Powder Player but not Powder Web, code needs to be moved to Powder Web: https://github.com/jaruba/PowderWeb/issues/16~
• ~Powder Web currently has no support for a Tray Icon on Linux, this should be fixed before implementing this as it would lead to bad UX: https://github.com/jaruba/PowderWeb/issues/1~
• Move Trakt & Metadata code from Powder Player