Define event for selecting other activity

Use case: In activity A I want to create a link to activity B, so that when the user clicks it the app will change the view to activity B.

A first place where this could be useful is the welcome page where we could add links to all the activities.

added To Do label

changed the description

We've now made the welcome activity special so it has direct access on the parent app-shell (which is the same package), so we no longer need this atm.

It might still be needed for future use cases, but let's close this for now.

closed