Repo updates

[alexjg]

This is a draft of the doc changes for automerge-repo. It currently consitsts of two things:

1. Updates to the quickstart and tutorial to use automerge-repo rather than raw automerge. This is pretty rough and ready structurally, I don't like it at all. I also haven't actually tried to run the code samples involved, but I'm putting together a vanilla JS demo for automerge-repo which I think we should be able to use for this purpose.
2. Add a git submodule for the automerge-repo typedocs. Getting the typedoc docusaurus pluging to work with this required adding all the dependencies of automerge-repo to the docs project which I really dislike. I also dislike using git submodules and I don't think the layout of the typedoc in docusaurus works particularly well, maybe we should just host the typedoc elsewhere rather than in docusaurus?