Make the demos load in a more performant way

[chasenlehara]

Right now, pages like the Technology Overview make thousands of http requests and load tens of megabytes of code because everything is loaded individually by steal.

Look into solving this with steal’s dev bundles feature.

[chasenlehara]

This is much improved but I think there’s still some room for improvement; we’re down to 200 requests and 7.1 MB (taking 16s to finish) at the time of this writing: