We can improve the genericness of ServerDescription by breaking out server addresses to their own type that can handle IPv4, IPv6, SRV and any potential future address types that could be added.

SDAM and CMAP were rewritten to abstract the endpoints we could connect to. We prefer names like address or uri to host and port because we might eventually want to connect to something that doesn't use a classic host/port (even domain sockets break this, but what if we wanted to connect to.. a file or something). We think adding host and port on ServerDescription is coupling the concerns of creating a TCP socket with something that shouldn't care about transports. So as part of this work we can remove those properties from ServerDescription.