autobrr support for ruTorrent v6

[stickz]

I would like to approve integrating autobrr into ruTorrent, once we start development of version 6. It is the modern replacement for autodl-irrsi, which many people used when it was supported. My vision for ruTorrent v6 is to have a single unified interface for modern tools like the arr suite. Their API docs are located here which returns a JSON response we can easily parse: https://autobrr.com/api

It's required to use curl (which we already support). The recommended implementation is to ask the user for their API key in the settings menu (on the developers tab), then save it to autobrr.dat. We can add a autobrr submenu to the plugin menu on the navigation bar. A custom plugin would need to be created, which the user can enable/disable.

Opening the autobrr menu would allow the user to:

1. List all filters from the autobrr instance.
2. Add new filters to the autobrr instance.
3. Update existing filters on the autobrr instance.
4. Delete existing filters from the autobrr instance.

There are more features on autobrr. If we start with this simple implementation, it would greatly improve the time and success of the project. We can build onto the implementation afterwards with abstraction layers, in the form of multiple successful pull requests.