Merging with openmc-reactor-examples

[rzehumat]

Hi,

I'm wondering if openmc-reactor-examples might be merged here, as it contains similar examples.

Thanks for any ideas here.

[pshriwise]

I'd be open to that though we might want to create folders for the existing notebooks, which are more about how to use the API, from the full reactor models. They'd also be coming from a different organization (both on github and in the real world) so we'd want to check with @bforget to get his thoughts and see if that would be desirable.