Add a how-to page about bitcoin layers and protocols #1069

There has been interest in having a good explainer for terms like Layer 2, Sidechain, Ordinals, etc. This new "How it works" page would try to clarify some of these mechanisms for a very basic understanding, without endorsing any of them. This would be in the same vein that the Stabilizing bitcoin value page explains different mechanisms outlining technological approaches with diagrams and usage examples, and breaking down the pros and cons.

Anyone who reads social media or news in this ecosystem will certainly have come across some of these terms. But what's the difference between a Sidechain and a Layer 2? Or Sidechains, Drivechains, Spacechains, and Spiderchains? What are these constructs optimizing for, and what are they compromising on? What role can they potentially play in scaling bitcoin, or enabling new use cases? What are the risk factors?

It will probably be tricky to not make this page overly complicated.

A first step before starting writing would be to do some basic research. Which terms do people have questions about? And then, maybe there are already great explainers out there that we can link to, or build on. Maybe we don't even need our own page. Either way, there has been interest in this, so it's something we can look into. I'll create a doc and share it in Discord to collect terms.