Support extensions for different types of probe messages

## Note
  - Add `extension_id`  to probe_settings where extensions could be none, joke, bible verse etc.
  - If extension is enabled, based on extension, get text & send back to user.

E.g. `joke` -  you get a joke with your probe, or `custom-questions` - you get a custom puzzle, if solved correctly, that means you're okay, `math` - get a random math problem each time to check if you're okay