RenetSteam: Adding support for socketaddress connection types

[AnthonyTornetta]

Closes #183

This adds support for multiple simultanious connection types in the SteamServerTransport and allows the SteamClientTransport to use them.

Feedback on this would be appreciated, as I am no steam networking expert.

This contains some public API changes, but I did update the README + docs to reflect the changes.

⚠️ This is still largely untested

So far I have only tested this using the localhost IP address.

The new API methods + SteamServerSocketOptions should also be given public docs. This will give people unfamiliar with the steam APIs an easier onboarding process.

[lucaspoffo]

Thanks, I will try taking a look this week, the localhost setup would really help to test locally.