Add new layouts

[sroussey]

This adds some new layouts. Uses a graph library for DAGs that I have been working on.

[clarkmcc]

Great! These layout engines can't be used without exporting through the lib/index.ts file though.

As a side note, I'm wondering if in the future we need to expose a better API for using builtin layout engines, since you have to work with those long function names like computePipelineLayout or computeDagreLayout and then assign them to a name, and then reference that name when calling the layout function. Check out my ChatGPT conversation about a possible type-safe design.

In any case, I'm approving assuming an export of the layout functions. I just wanted to regurgitate some of my thoughts so that they can guide design decisions in the future.

[sroussey]

I refactored, so have a look.

[sroussey]

Also, I needed a graph lib, and typescript-graph was the first I found. It is simple, but ended up being too simple so I forked it to add the things I need and is used in this PR as @sroussey/typescript-graph

[clarkmcc]

lgtm!