Option to create a new project

Received via internal bug feedback tool:

> This is my second run trying out the Run Deploy and I figured it out so this screenshot isn't relevant but I think it'd be helpful if:
> 1. After you select a project and get an error message, you can select another one instead of just being stuck trying to fix payment options for that project
> 2. Be clearer about how to add a payment method and how much that payment will be. Just link to it more directly

tl;dr consider adding "New Project" option to the project selector, and handle billing errors in a more friendly way.