Meaningful dial addresses for easier debugging

As you can see, it's easier to see what is what in gRPC debug logs.

{"level":"info","time":"2024-05-03T13:38:59.351+1000","msg":"Running KAS gitlab-kas/v0.0.0/00000000"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"Using own private API URL","url":"grpc://172.16.123.1:8155"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Channel #1]Channel created"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Channel #1]original dial target is: \"passthrough:private-server\""}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Channel #1]parsed dial target is: resolver.Target{URL:url.URL{Scheme:\"passthrough\", Opaque:\"private-server\", User:(*url.Userinfo)(nil), Host:\"\", Path:\"\", RawPath:\"\", OmitHost:false, ForceQuery:false, RawQuery:\"\", Fragment:\"\", RawFragment:\"\"}}"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Channel #1]Channel authority set to \"private-server\""}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Server #2]Server created"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Server #3]Server created"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Server #4]Server created"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Server #5]Server created"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Channel #6]Channel created"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Channel #6]original dial target is: \"passthrough:internal-server\""}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Channel #6]parsed dial target is: resolver.Target{URL:url.URL{Scheme:\"passthrough\", Opaque:\"internal-server\", User:(*url.Userinfo)(nil), Host:\"\", Path:\"\", RawPath:\"\", OmitHost:false, ForceQuery:false, RawQuery:\"\", Fragment:\"\", RawFragment:\"\"}}"}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Channel #6]Channel authority set to \"internal-server\""}
{"level":"info","time":"2024-05-03T13:38:59.355+1000","msg":"[core] [Server #7]Server created"}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"Kubernetes API endpoint is up","mod_name":"kubernetes_api","net_network":"tcp","net_address":"172.16.123.1:8154"}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"[core] [Server #7 ListenSocket #8]ListenSocket created"}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"Observability endpoint is up","mod_name":"observability","net_network":"tcp","net_address":"127.0.0.1:8151"}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"Private API endpoint is up","net_network":"tcp","net_address":"172.16.123.1:8155"}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"API endpoint is up","net_network":"tcp","net_address":"172.16.123.1:8153"}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"[core] [Server #2 ListenSocket #10]ListenSocket created"}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"[core] [Server #5 ListenSocket #11]ListenSocket created"}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"[core] [Server #3 ListenSocket #9]ListenSocket created"}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"Agentk API endpoint is up","net_network":"tcp","net_address":"172.16.123.1:8159","is_websocket":true}
{"level":"info","time":"2024-05-03T13:38:59.357+1000","msg":"[core] [Server #4 ListenSocket #12]ListenSocket created"}