fix nodes grouping and uptime calculations (#10075)

Author: adameat

ydb/core/viewer/json_handlers_viewer.cpp

@@ -243,7 +243,7 @@ void InitViewerHealthCheckJsonHandler(TJsonHandlers& handlers) {
 }
 
 void InitViewerNodesJsonHandler(TJsonHandlers& handlers) {
-    handlers.AddHandler("/viewer/nodes", new TJsonHandler<TJsonNodes>(TJsonNodes::GetSwagger()), 8);
+    handlers.AddHandler("/viewer/nodes", new TJsonHandler<TJsonNodes>(TJsonNodes::GetSwagger()), 9);
 }
 
 void InitViewerACLJsonHandler(TJsonHandlers &jsonHandlers) {

ydb/core/viewer/protos/viewer.proto

@@ -525,6 +525,11 @@ message TNodeGroup {
 
 message TNodeInfo {
     uint32 NodeId = 1;
+    string Database = 2;
+    int32 UptimeSeconds = 3; // negative for disconnect time
+    bool Disconnected = 4;
+    float CpuUsage = 5;
+    float DiskSpaceUsage = 6;
     NKikimrWhiteboard.TSystemStateInfo SystemState = 10;
     repeated NKikimrWhiteboard.TPDiskStateInfo PDisks = 20;
     repeated NKikimrWhiteboard.TVDiskStateInfo VDisks = 30;