Package alterator-module-executor: Information

- Fix forced process termination and its child processes. Before this fix,
  when the spawned process was forcefully terminated, its child processes were
  not terminated.

- Add the ability to emit unicast signals upon request from an executable
  file. Signals are sent to the user who called the method. The executable
  file sends a message in JSON format to file descriptor number 3. The message
  specifies the name and body of the signal.

- Update secret scan action to use alterator fork (the-nexi@).