[docs] Add `supernova` to the docs

[leohhhn]

Description

This issue concerns adding a guide on how to stress test your Gno network with supernova. This tutorial could live in the How-to guides section from the perspective of Diataxis; but a more logical location might be somewhere in the gno-infrastructure section, as it concerns infra.

[leohhhn]

Following internal communication with @Kouteki I'll take myself off of this task.