External events and reminders should trigger intents instead of actions

Description of Problem: Reminders and external events always trigger actions, which contradicts the logic that actions should be unambiguously predictable from the dialog history and present intent. For example, in the use case where a reminder is used to have the bot initiate chitchat, this makes stories unlearnable.

Overview of the Solution: External events and reminders should trigger intents, not actions, since intents are the things that are out of our control and actions should be deterministic. Now that we have a mapping policy, this has no drawbacks.

For some applications and backwards compatibility, triggering actions should still be possible, so both options have to be available.

Examples (if relevant): If we want to set a reminder to have the bot initiate chitchat, we would now trigger the intent, say, EXT_remind_share_me, which is linked to the action utter_share_me via the MappingPolicy. This results in stories of the form

* EXT_remind_share
  - utter_share_me
* general_confirm
...

which can be learned and are readable.

Definition of Done:

• Tests are added
• Feature described in the docs
• Feature mentioned in the changelog

[akelad]

@JEM-Mosig my initial thought is can we call the WorldMessaged something more intuitive? E.g. ExternalEvent or something - not sure if that’s the right one either, but WorldMessaged sounds a bit weird to me

[wochinge]

Summary of call

• No external event class
• Endpoint POST "/conversations/<conversation_id>/trigger/<intent>"
• is_external metadata for these events (Rasa X UI can hide them then)

@tmbo We would create a new endpoint to trigger intents. We could also

• use the rest inputchannel, but it would be weird to send the output of the actions to a different user and to set the is_external metadata
• use the appendEvents endpoint, but that doesn’t trigger prediction .

Is that ok?