daemon: implement 'set_bootstrap_daemon' command

src/daemon/rpc_command_executor.h

@@ -162,6 +162,11 @@ public:
   bool check_blockchain_pruning();
 
   bool print_net_stats();
+
+  bool set_bootstrap_daemon(
+    const std::string &address,
+    const std::string &username,
+    const std::string &password);
 };
 
 } // namespace daemonize