A session with cookies

usage

```rust use asession::SessionBuilder;

[tokio::main]

async fn main() { let session: Session = SessionBuilder::new() .cookiesstoreinto("cookies.json".into()) .build().unwrap();

let res = session.post("https://www.example.com")
    .form(&[("key", "value")])
    .send()
    .await
    .unwrap();

} ```