Remove remnants of thebe / console app

[stefanv]

For numpy.org, we should (1) add thebe.js into static/js containing:

<!-- Thebe Configuration -->
<script type="text/x-thebe-config">
    {
        requestKernel: true,
        binderOptions: {
            repo: "joelachance/thebelab-requirements"
        },
    }
</script>

(2) Also ensure that static/js/app.js is present still.

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