Improve onboarding empty state when users have no scripts

[anthonyec]

Current onboarding text

You don't have any
bookmark scripts.

This doesn't really explain where scripts can be added to show up in Powerlets.

[anthonyec]

Inspired by Spotify podcasts screen.

Title: You don't have any bookmark scripts.
Message: When you save scripts to your bookmarks, they'll automatically show up here.

[anthonyec]

https://bide.onodi.co/