polySolvePage `details` documentation

[forresto]

For other design systems to preheat imgflo, etc. https://github.com/the-grid/pipeline/issues/10

[forresto]

@jonnor until in the docs, what should 'nilla return for imgflo preheat?

[jonnor]

details should be an object. If it contains a key images with an array of image URLs for imgflo, we will (eventually) POST those to imgflo to preheat the cache.