Use driver.js for very basic 'new scratch' tutorial

[mkst]

Creating this for comments rather than because it should be merged. It's very basic, and am probably doing things horribly... but thought it's worth a discussion.

Ideally it would be able to add some target asm, and context.. but calling setAsm("nop") didnt cause react to re-render, so I've parked that for now.

Edit: I'll look at swapping out driver.js for https://github.com/josias-r/boarding.js