Replace get_if_addrs with a pure Rust library

[tomaka]

For the sake of not having to compile any C code, let's try use only pure Rust dependencies.

[mxinden]

We could use libpnet's interfaces instead which for unix would use the systems libc instead of custom C code.

[Demi-Marie]

Once https://github.com/paritytech/ip-watch is ready, this will be solved.

[kallisti5]

It looks like this one is solved? Having trouble building apps using rust-libp2p 0.22.0 because of poor "non-linux" support. get_if_addrs is also now read-only and not accepting patches / fixes.

[mxinden]

It looks like this one is solved?

Not quite. I am afraid it gotten even more complicated.

With #1830 libp2p-mdns now uses if-wtach which uses a Rust implementation on Linux and Windows and falls back to if-addrs on e.g. Mac.

libp2p-tcp still uses if-addr which might change to if-watch with #1845.

[dvc94ch]

this one can be closed now, no?