Convert "usage question" issues to discussions

[andersy005]

@pydata/xarray

The number of open issues has been growing steadily ¹. Some of the issues are purely usage questions. In an effort to reduce the issue backlog, I was wondering if we could convert these usage questions to discussions instead?

Footnotes

1. Dashboard ↩

[shoyer]

Sounds good to me for clear usage question. But discussions is also a limited format, really best for Q&A. So if someone has a true discussion topic, I'm also OK with an issue.