Support for notebook v7

This ticket tracks changes needed to support Notebook v7 in the home app.

I did a brief test by opening all various notebook files by running `jupyter notebook .ipynb` (i.e. I ran outside of Appmode), here's a list of problems I found (there might be more of course).

1. `IPython` object on the JS side does not exist, so the following code relying on it fails, for example
```js
%%javascript
IPython.OutputArea.prototype._should_scroll = function(lines) {
return false;
}
```

2. The Terminal app is broken

CC @unkcpz