Add notebook launch links

[Pinpickle]

This adds launch links for notebooks that look like this:

They let users go straight to the notebook runner, rather than constructing the URL themselves.

I've added them inside the notebooks themselves, and near any major link to the notebook (e.g. in README.md)

I've also added Deepnote launch links (disclaimer: I work at Deepnote). I've added them as the first link as they don't require users manually upload datasets unlike the other options, so that's the most convenient unless they're familiar with the other services. They just need to click the button and everything is ready to go.

[alexeygrigorev]

What's the best way to contact you and discuss it?

[Pinpickle]

@alexeygrigorev happy to chat about it - send me an email at [email protected]