unified-storage: setup ring to shard requests (#103783)

* Updates the instrumentation_server service to use mux instead of the builtin router, and have it store the router in the module server: this is so we can register the /ring endpoint to check the status of the ring
* Create a new Ring service that depends on the instrumentation server and declares it as a dependency for the storage server
* Create standalone MemberlistKV service for Ring service to use
* Update the storage server Search and GetStats handler to distribute requests if applicable

pkg/setting/setting.go

@@ -547,6 +547,11 @@ type Cfg struct {
 	IndexMaxBatchSize           int
 	IndexFileThreshold          int
 	IndexMinCount               int
+	EnableSharding              bool
+	MemberlistBindAddr          string
+	MemberlistAdvertiseAddr     string
+	MemberlistJoinMember        string
+	InstanceID                  string
 	SprinklesApiServer          string
 	SprinklesApiServerPageLimit int
 	CACertPath                  string