SDK: Documentation and Extensions

[nud3l]

Is your feature request related to a problem? Please describe.
The SDK has little documentation and we hadn't had time yet to bring it to a state where others can easily use it or contribute to it.

ToDos

For Bitcoin Asia

• Add install instructions for BOB SDK to docs #178
• Extend the Hello Bitcoin example (https://docs.gobob.xyz/docs/build/getting-started/helloworld) to show how to use the BOB SDK from a node.js script to (1) submit Bitcoin block headers to the deployed relay, (2) fetch the transaction inclusion proofs from electrs, and (3) submit the transaction inclusion proof to the BTC Relay.

Others

• Add an overview to the docs of the SDK what the different components do, e.g., electrs, ordinals, helpers
• Replace bitcoinjs-lib dependency with https://github.com/paulmillr/scure-btc-signer everywhere