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/storage/unified/sql/server.go

@@ -21,7 +21,7 @@ import (
 func NewResourceServer(db infraDB.DB, cfg *setting.Cfg,
 	tracer trace.Tracer, reg prometheus.Registerer, ac types.AccessClient,
 	searchOptions resource.SearchOptions, storageMetrics *resource.StorageMetrics,
-	indexMetrics *resource.BleveIndexMetrics, features featuremgmt.FeatureToggles) (resource.ResourceServer, error) {
+	indexMetrics *resource.BleveIndexMetrics, features featuremgmt.FeatureToggles, distributor *resource.Distributor) (resource.ResourceServer, error) {
 	apiserverCfg := cfg.SectionWithEnvOverrides("grafana-apiserver")
 	opts := resource.ResourceServerOptions{
 		Tracer: tracer,
@@ -68,6 +68,7 @@ func NewResourceServer(db infraDB.DB, cfg *setting.Cfg,
 	opts.Lifecycle = store
 	opts.Search = searchOptions
 	opts.IndexMetrics = indexMetrics
+	opts.Distributor = distributor
 
 	rs, err := resource.NewResourceServer(opts)
 	if err != nil {