Invalid port is not logged in async startup

[fliiiix]

New feature to log that the port is already used instead of just timeouting.

Consider the following example:

#include "crow_all.h"

int main(int /*ac*/, char ** /*av*/) {
  CROW_LOG_INFO << "Playing some music";

  crow::SimpleApp app;

  CROW_ROUTE(app, "/")
  ([]() { return "Hello World";  });

  app.loglevel(crow::LogLevel::DEBUG);
  app.bindaddr("0.0.0.0").port(8000).multithreaded().run_async();

  CROW_LOG_INFO << "Before wait";
  auto status = app.wait_for_server_start();
  CROW_LOG_INFO << "After wait";

  if (status == std::cv_status::timeout)
  {
    CROW_LOG_INFO << "Timeout";
  }
}

Which logs this if the port is already used (or nothing without custom logs)

(2024-11-26 12:01:46) [INFO    ] Playing some music
(2024-11-26 12:01:46) [INFO    ] Before wait
(2024-11-26 12:01:49) [INFO    ] After wait
(2024-11-26 12:01:49) [INFO    ] Timeout

Vs the error you get with run()

(2024-11-26 12:01:11) [INFO    ] Playing some music
terminate called after throwing an instance of 'std::system_error'
  what():  bind: Address already in use
[1]    1518945 IOT instruction  ./src/radiopi

The address is already validated with: #918 logging