Use Playwright for alternative to `eval` bundle

[pmalacho-mit]

Currently, there is a sketchy aspect of the bundling process which requires executing an extensions bundle using the eval function. In addition to this being sketchy, it also can cause issues as the execution environment is node, since the bundling process is being run by node.

(NOTE: This step is necessary to surface the extension details of a given extension class -- this works because the mixin functions that define an extension class are executed immediately, as opposed to when an extension instance is instantiated)

This fact is making it difficult for @mayarajan3 to use a library like magenta in her extension.

Here's the current code that handles this: https://github.com/mitmedialab/prg-extension-boilerplate/blob/dev/extensions/scripts/bundles/plugins.ts#L207