The delete_stale_pid_file check for the daemon is fragile

[sphuber]

The aiida.cmdline.utils.daemon.delete_stale_pid_file was added to automatically detect and clean up stale PID files for the daemon. However, it is kind of fragile as it does not take into account that the PID file might be on a shared file system and the daemon was actually started from a different machine with access to the same file system. Ideally, the hostname could be included in the PID file to try and distinguish this case, in which case an error should be raised instead of removing the PID file.