Add pangeo-forge-runner init <initializer> command?

[cisaacstern]

Discussion in yuvipanda/pangeo-forge-cmr#4 (comment) made me wonder if this would make sense, as noted there this would basically be npm init, but for Pangeo Forge feedstocks, and the optional <initializer> would be pluggable.

It's more work, of course 😆 , but could a meaningful way to reduce the barrier to entry for new users, insofar as getting the repo structure right is a consistent challenge I've observed (even in myself).

[yuvipanda]

I like.