Dask Enhancement Proposals

Hello everyone,

I would like for us to consider adopting an enhancement proposal process. Github issues and PRs are good for day-to-day feature development, but larger efforts tend to get a bit scattered among several issues/blogposts/in-person conversations.

Historically I tracked larger issues personally and served as the human reference/collection point for larger planning. As I've been less active over the last few months this role seems to have gone dormant. This has happened in other projects before. For example Numpy seemed to benefit from the NEP process when that started.

I'm inclined to start brain-dumping a bunch of larger thoughts in my head down (recommended by @crusaderky). These might serve as a first set of DEPs and a good use case to flesh out this process. I'm inclined to learn about and start with the NEP structure if no other ideas come up before that.

cc @shoyer @quasiben