docs: add xrpl.js code snippets over to xrpl-py

[connorjchen]

High Level Overview of Change

Ported xrpl.js code snippets over to xrpl-py

Context of Change

Code snippets are a great way for developers in the community to learn from

Type of Change

• Documentation Updates

Test Plan

Ran each file individually (claim_payment_channel fails because missing hashing function now)

[mvadari]

I would write these with the JsonRpcClient (unless you want to write a snippet with each client, which seems like too much).

[mvadari]

A couple of notes:

• Please add a multisign snippet (this could be in a separate PR if you'd prefer)
• Please add these as tests (this would probably best done by importing the file in a test, since the file will run when it's imported)