Remove inconsistent address resolution

[PetrichorIT]

There is an inconsistency in address resolution / parsing.
The trait ToIpAddr interprets strings that can be parsed as an IpAddr as
domain names instead of parsing the address. ToSocketAddr however will
parse the Ip part of the address if possible. To remove this inconsistency
ToIpAddr will now always interpret strings that can be parse to a IpAddr as IpAddr.

Example

Without this change:

use turmoil::{*, net::*};

fn main() -> Result {
    let mut sim = Builder::new().build();
    sim.client("192.168.42.42", async move {
        let addr = UdpSocket::bind("0.0.0.0:0").await.unwrap().local_addr().unwrap();
        // addr will be 192.168.0.1:<port>, interpreting the clients name as a domain addr
        Ok(())
    });
    sim.client("192.168.57.57".parse::<IpAddr>().unwrap(), async move {
        let addr = UdpSocket::bind("0.0.0.0:0").await.unwrap().local_addr().unwrap();
        // addr will be 192.168.57.57:<port>, respecting the provided parameter
        Ok(())
    });
   
   // The problem is even more pronounced with lookups
   sim.client("x", async move {
        // lookups will use the ip->ip dns entry
        assert_eq!(lookup("192.168.42.42"), Ipv4Addr::new(192,168,0,1));
       
       // ToSocketAddr however not use dns but rather parse the raw ip part
       // Thus this will panic, since the link `x->192.168.42.42`does not exits
       let stream = TcpStream::connect("192.168.42.42:80").await?;
       Ok(()) 
   });

  sim.run()
}

On a site note, ToIpAddr was not implemented for Ipv4Addr and Ipv6Addr which
was problematic since APIs with impl ToIpAddr could not use .into() due to missing
type inference. Same goes for ToSocketAddr with SocketAddrV4 and SocketAddrV6 respectivly
(Tokio's ToSocketAddr does is implemented for these types)

[mcches]

Thanks for making the Addrs more complete!