[FEAT] server selection with availability_zone awareness support

[KLuuKer]

Some servers (valkey) will reply with availability_zone in the HELLO reply.

It would be nice (for pure latency overhead), to always attempt to connect to servers in the same zone as the client.

Usefully when running a cluster with multiple shards where each share has a replica in each zone.

[mgravell]

Thanks. I'm currently working on related functionality, so will see if this can be accommodated easily.