[Feat]: Trigger response via external app request

[ThreeDeeJay]

Description
It would be useful if we could trigger responses by sending the prompt to PocketPal as a searchable app or programmatically like broadcast intent.

Use Case
Using a voice assistant like Utter/Saiy for voice prompt so that PocketPal immediately loads a default/specific model and either display the response in the app or Text-To-Speech and/or an overlay, perhaps even in the background for least possible friction.

A currently functional, similar example is how we can use those voice assistants to create a command to play specific music immediately by saying something like play <ARTIST>/<TRACK>/<ALBUM>