Throttle sorting just a touch

src/mesh/NodeDB.h

@@ -282,6 +282,7 @@ class NodeDB
     bool duplicateWarned = false;
     uint32_t lastNodeDbSave = 0;    // when we last saved our db to flash
     uint32_t lastBackupAttempt = 0; // when we last tried a backup automatically or manually
+    uint32_t lastSort = 0;          // When last sorted the nodeDB
     /// Find a node in our DB, create an empty NodeInfoLite if missing
     meshtastic_NodeInfoLite *getOrCreateMeshNode(NodeNum n);