Spike: Consider alternatives to using "debug"

[JanLenoch]

Expected result

In reaction to gatsbyjs/gatsby#8053, we re-wrote the plugin to get data from the debug property of the JS SDK response object. But, the debug property was not meant to be used for other than debugging purposes.

Consider the alternative approaches:

• De-conversion of class instances produced by the SDK back into plain JS objects using a library (eg. https://www.npmjs.com/package/flatted)
• Writing our own recursive de-conversion method (similar to https://stackoverflow.com/a/34701165/4074527)

Also, consider the performance impact of the de-conversion in environments like Netlify.