[Enhancement] Document potential endpoints for rtorrent/rutorrent users

[HrBingR]

This is probably my inexperience more than anything else, but I'd suggest an optimization for the README.

Currently it describes TORRENT_CLIENT_URL as:

The full URL to your torrent client WebUI (e.g., http://192.168.1.10:8080 or http://qbittorrent:6767 if on the same Docker network).

Which is great for local setups, but it might be worth documenting somewhere that for users with rtorrent/rutorrent-based seedboxes, that the rutorrent URL won't work as-is, and that they'll likely have to use something to the effect of https:///rutorrent/plugins/httprpc/action.php for it to work, as a number of seedbox providers don't provide a direct XML-RPC interface for rtorrent, which meant in my case I had to use rTorrent's httprpc plugin endpoint with the app.

Other than that, the app is working fabulously!

[sevenlayercookie]

Thank you for the suggestion! I was unaware of that. I will add some more documentation