daemon: auto public nodes - cache and prioritize most stable nodes

tests/unit_tests/CMakeLists.txt

@@ -34,6 +34,7 @@ set(unit_tests_sources
   blockchain_db.cpp
   block_queue.cpp
   block_reward.cpp
+  bootstrap_node_selector.cpp
   bulletproofs.cpp
   canonical_amounts.cpp
   chacha.cpp