feat: query-backend read path (#3524)

* add read path router scratches

* fix segment writer client sent bytes metric

* wire up querier methods

* implement frontend for backend

* remove unused fields

* init read path router

* register VSC metrics in idempotent way

* stack trace query format

* implement pprof query

* add unit tests for read path router

* Fix typo in file name

.mockery.yaml

@@ -11,4 +11,6 @@ packages:
   github.com/grafana/pyroscope/api/gen/proto/go/metastore/v1:
     interfaces:
       MetastoreServiceClient:
-
+  github.com/grafana/pyroscope/api/gen/proto/go/querier/v1/querierv1connect:
+    interfaces:
+      QuerierServiceClient: