Add etcd as a service discovery mechanism

go.mod

@@ -14,7 +14,7 @@ require (
 	github.com/lestrrat-go/file-rotatelogs v2.4.0+incompatible // indirect
 	github.com/mitchellh/mapstructure v1.5.0
 	github.com/openimsdk/protocol v0.0.65
-	github.com/openimsdk/tools v0.0.49-alpha.14
+	github.com/openimsdk/tools v0.0.49-alpha.15
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/prometheus/client_golang v1.18.0
 	github.com/stretchr/testify v1.9.0