qBittorrent web api for Rust

This is an automatic async implementation of the qBittorrent 4.1 web api. The api generation is based on the wiki markdown file which can be found here.

Example

```rust use anyhow::Result; use qbittorrentwebapi::Api;

[tokio::main]

async fn main() -> Result<()> { let api = Api::login("http://localhost:8080", "admin", "adminadmin").await?;

// add a torrent
api.torrent_management()
    .add("http://www.legittorrents.info/download.php?id=5cc013e801095be61d768e609e3039da58616fd0&f=Oddepoxy%20-%20Oddepoxy%20(2013)%20[OGG%20320%20CBR].torrent")
    .send()
    .await?;

// critical logs
let logs = api.log()
    .main()
    .critical(true)
    .warning(false)
    .normal(false)
    .info(false)
    .send()
    .await?;

println!("{:#?}", logs);

// current torrent info
let info = api.torrent_management().info().send().await?;

println!("{:#?}", info);

Ok(())

}

```