Add support for discovery server

[Logout22]

I wrote a simple discovery server to avoid having to exchange IP addresses manually. It can be found here:

https://github.com/Logout22/crowdchat-rs-server

I would be happy to merge the server repo into the rustdresden project as well.

Thanks for reviewing!

[whimboo]

Hm, I'm not the perfect reviewer for the code yey, so I started to at least have a look in how to get it running. But building the binary via cargo run fails for me in two places (lines 34 and 40):

34 |         send_socket.send_to(wire_format.as_bytes(),addr).unwrap();
   |                     ^^^^^^^ the trait `std::net::ToSocketAddrs` is not implemented for `std::string::String`

[hoodie]

that particular feature has landed in 1.16 of the standard library, so you're probably only one rustup update away from compiling 😁

https://github.com/rust-lang/rust/blob/master/RELEASES.md
rust-lang/rust#39048

[hoodie]

sorry for the close