Not all intents are invokable with AppIntent

## Issue description
The [AppIntent rpc method](https://github.com/digital-dream-labs/vector-cloud/blob/main/internal/proto/external_interface/external_interface.pb.go#L217) does not seem to be able process and invoke all the available and existing intents, but just only few of them. To cherry pick some examples:
For example following intents can be invoked with API:
- knowledge_question
- explore_start
- intent_names_ask
But following intents not, so they can be invoked as voice commands only:
- set_timer
- take_photo
- show_clock
etc....

Also, there seems to be no public documentation for the AppIntentRequest params, so would be very appreciated to have some reference to it, if possible.