This strategy checks the key presented by the host with the one printed out in the instance console. The key should
be printed with the format "algorithm key". Example: ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJbvbEIoY3tqKwkeRW/L1FnbCLLp8a1TwSOyZHKJqFFR
If the key is not found because the console is blank, the connection is closed and wait until console prints something.
If the key is not found because the instance doesn't print any key, the connection is trusted.
If it's found and the key presented by the instance doesn't match the one printed in the console, the connection is closed
and a warning is logged.
If the key is found, it's stored to check future connections.