Describe how a BTC light client works

[nud3l]

Is your feature request related to a problem? Please describe.
We often get asked how to achieve trustless communication between Bitcoin and BOB. For example, swapping ordinals with ERC20 prompts most people that we talked to think that the ordinals need to be bridged. However, in a P2P fashion, bridging isn't required.

Describe the solution you'd like
Add a section to the docs, likely under here https://docs.gobob.xyz/docs/learn/guides/, that explains the principles of how a BTC light client works, what the trust assumptions are, and what applications can be built with this.

Additional context
The description should be SEO-friendly so we start building up a useful wiki for builders.

We can reuse text from the interBTC spec: https://spec.interlay.io/spec/btc-relay/index.html

[gregdhill]

@derrekcoleman is this something we already have?

[derrekcoleman]

We have three pages mainly about or using the light relay.

• Conceptual introduction
• Step-by-step guide for swap
• Step-by-step guide for Hello World-type basic usage

They aren't perfect pages, but I wonder how much time we should invest if we're going to want docs based on an upcoming Full Relay sometime in the future. wdyt @gregdhill?

[gregdhill]

Hmm yes maybe it would make sense to add something about the Full Relay.