Mark the networking module as deprecated

[arthuro555]

While my knowledge of rust is limited, as far as I can tell, the networking module of steamworks-rs is being used, which uses the deprecated ISteamNetworking:

As such, it would be great if the networking module could be marked as deprecated (i.a. via the /** @deprecated */ JSDoc comment), so that IDEs warn about the state of this API properly. It would be even greater if these bindings could include the newer networking APIs that replace it as well ;)